The Ford Torino Page Homepage
Forum Home Forum Home > Model Specific Forum > 1977-1979 Ford and Mercury
  New Posts New Posts RSS Feed - Blower won't blow
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Blower won't blow

 Post Reply Post Reply
Author
Message
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Topic: Blower won't blow
    Posted: 30-October-2022 at 11:25AM
77 Thunderbird with factory AC. When I bought it, the guy said it needs a new blower. Fine, replaced that, still no blow. I verified the blower works by connecting it to a 12v source. Verified ground is good. Checked for power while the car is on - interesting result, with the car running I get 14v from the orange wire that feeds the blower, but the blower refuses to chooch. I did notice the fan selector switch was unplugged, got that hooked back up, no difference - my understanding is with that disconnected it should have just run the blower on high all the time.

Vacuum lines here all seem good, btw, though they are covered with what might be oil. I haven't traced down all the vacuum actuators and checked their function, but that shouldn't matter anyway, right?

The 14v but no blow is tripping me up. Any suggestions?
Back to Top
78FordLtd2 View Drop Down
Member
Member
Avatar

Joined: 19-April-2021
Location: Canada
Status: Offline
Points: 160
Post Options Post Options   Thanks (0) Thanks(0)   Quote 78FordLtd2 Quote  Post ReplyReply Direct Link To This Post Posted: 30-October-2022 at 12:56PM
Did you check all of the fuses?

Might even be the sliding power switch is dirty or not making contact 
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 30-October-2022 at 2:38PM
I did go through and check fuses, using the layout found here:


My fuse box is pretty crusty, but this seems to be the same one, and from what I can cobble together I've got a good fuse in both 8 and 6.

I did go ahead and impulse buy another fan speed switch. $10 for new-old-stock on ebay, easy way to knock that out of the running for possible causes.

I've seen many similar problems listed for other vehicles being listed as an issue with a blower resistor, but this car doesn't seem to have one of those.
Back to Top
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 14609
Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 30-October-2022 at 9:38PM
 there's a switch in 1 of the sliding levers!!! is an off and on switch, the lower switch is low, med., high
JOHN
74 GRAN TORINO S&H CLONE
74 VETTE CUSTOM
90 S10 BLAZER 4X4 LIFTED
77 CELICA CUSTOM
75 V8 MONZA SUPERCHARGED
79 COURIER VERT. SLAMMED
75 VEGA V6 5 SPD
70 CHEV C10 P/U
68 MUSTANG FB CONVERSION
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 31-October-2022 at 1:09AM
I am wondering if all the oil on the mechanism of that middle slider is interfering with something. Would I get voltage at the blower if that was the culprit, though? 

I'm also wondering where the oil has come from. It doesn't seem like engine oil or atf. I did have a leaky master cylinder. How crazy would it be to think that my brake booster (which works perfectly well) is full of fluid and that's made it's way into all the vacuum lines?
Back to Top
78FordLtd2 View Drop Down
Member
Member
Avatar

Joined: 19-April-2021
Location: Canada
Status: Offline
Points: 160
Post Options Post Options   Thanks (0) Thanks(0)   Quote 78FordLtd2 Quote  Post ReplyReply Direct Link To This Post Posted: 31-October-2022 at 11:58AM
I'm not sure where the oil would have come from. Unless someone before you had removed the control box looking for the same problem as you are and sprayed some kind of lubricant in it to free the levers. Have no idea.

The center slider is the "on-off" switch for the blower. The vacuum lines all operate various doors to direct the air flow. There is a copper contact on this center slider that powers the blower notor and it might be bent or missing. Or it might be dirty from all this oil you mentioned.

Where I'd start is removing the heater control box from the dash and try cleaning it up catrfully. Get as much of the oil out of it and other crap. If that does not work, I'd look for another control box. If you have power going to it, it should work. I dont think it is the blower motor at all or the speed switch.
Back to Top
qcode72 View Drop Down
Member
Member


Joined: 18-October-2013
Location: greenville,pa
Status: Offline
Points: 68
Post Options Post Options   Thanks (0) Thanks(0)   Quote qcode72 Quote  Post ReplyReply Direct Link To This Post Posted: 31-October-2022 at 12:21PM
Also check the plug wires on blower swith,they someetimes melt and burn wire on back of fuse block off.
Back to Top
72 RS 351 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 04-September-2014
Location: Knoxville TN
Status: Offline
Points: 2767
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72 RS 351 Quote  Post ReplyReply Direct Link To This Post Posted: 31-October-2022 at 3:35PM
Is there a blower motor resistor? That's a weak link item that eventually will burn the contacts or the terminals themselves.
Don
73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000+ rpm 351-4V &4R70W
73 Ranchero GT 351C-4V &4R70W for sale later.
92 Lincoln Mark VII SE GTC, OBDII 347/4R70W
Back to Top
bamatorino73 View Drop Down
New Member
New Member


Joined: 06-September-2018
Location: Pinson Alabama
Status: Offline
Points: 11
Post Options Post Options   Thanks (0) Thanks(0)   Quote bamatorino73 Quote  Post ReplyReply Direct Link To This Post Posted: 31-October-2022 at 5:44PM
There are two slide levers, plus the low medium and high switch. The top one is for temperature control. The lower one is for off, vent, a/c, low/hi, heat and defrost. Need that lever in anything but off position for the blower to work. The vacuum lines only opens or closes the doors conroled by the actuators.
cdavis 73 GTS 351c Q laster stripes
Back to Top
aquartlow View Drop Down
Senior Member
Senior Member


Joined: 19-December-2011
Location: Summerfield, Fl
Status: Offline
Points: 2271
Post Options Post Options   Thanks (0) Thanks(0)   Quote aquartlow Quote  Post ReplyReply Direct Link To This Post Posted: 31-October-2022 at 11:11PM
If you are getting 14V from positive lead that supplies voltage to blower(at blower) as stated in your original post, check the other wire/terminal at blower for a good ground. You may need to add a separate ground for the blower motor, although the ground source for the blower also is the ground source for other components and may need attention to get everything else on that circuit working correctly. If you do run a new ground wire/lead to blower motor, it may be advantageous to connect it to the current ground wire running to the blower which may help the other components as well without having to tear apart the dash to find the suspect ground if one exists. Hope this helps   
www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires.

No matter how good she looks, somebody, somewhere, is tired of her sh*t.

Beauty is skin deep, ugliness goes clear to the bone.
Back to Top
Greg73Oregon View Drop Down
Senior Member
Senior Member


Joined: 23-February-2021
Location: Roseville, CA
Status: Offline
Points: 232
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg73Oregon Quote  Post ReplyReply Direct Link To This Post Posted: 01-November-2022 at 7:52AM
Grounding - Ditto!!! Thumbs Up
Also, check the speed control resistors (nichrome wire).  Sometimes they burn open.
GKF
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 01-November-2022 at 9:53AM
I managed to steal 45 minutes to work on this today. I very much appreciate everyone's suggestions. Managed to work through a few items, no luck yet.

 - Blower still chooches if wired straight to a battery.

 - The on/off in the middle slider on/offs properly - 14v in any running position, nothing when off.

 - Found the resistor - it's under the hood, stuck into the AC housing. That was corroded all to hell, but after cleaning up the connections I did get continuity from post to post. Cleaned up the connectors in the boot, pretty confident that's in good shape now and wasn't before. Didn't have time to check resistances, but as I understand it that shouldn't matter for this situation? Maybe I'm wrong there - will check that.

 - I did change the grey plug that goes into the speed selector switch under the dash. Near as I can tell, that wires to the resistor. The original plug was all smashed up and disconnected - when I wired the new one I went by the old arrangement, but I wonder if previous owner may have fudged which wire plugs in where.

 - Checked voltages again. With the car on and the system on, I get 14v from hot to ground. If I connect up the motor and test that, I get nothing. I'm no electrical engineer here, but it seems like a 100% voltage drop is a little excessive.

All of this leads me to believe it is the one thing I didn't check today - the quality of the ground. The blower is grounded straight to the metal of the body, and while the multimeter says I've got that continuity, I'm wondering if it's just not enough ground for the motor. Is that a thing?

My next move will be to hotwire to the car's battery. First hot to blower while the car is off, which should check the chassis ground for me, and then ground to blower while the car and system is on. We'll just see what happens there.


Edited by derth - 01-November-2022 at 10:02AM
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 01-November-2022 at 2:57PM
Found a wiring diagram for this business posted by user aquartlow back in 2014:


After beating my head on this page for a while, I've figured out that the system should default to fan speed low if the speed selector is unplugged. I get 14v if the car and system is on, no matter what, which is definitely not low.

Still thinking I might have a poor ground. Now thinking I might also have a shorted resistor. It's also possible a previous owner tried to bypass the resistor - the blower wasn't attached to the car very well, so someone could have been up there doing something.

Adding to my list, pull the plug on the resistor and see if I lose the 14v.

In the back of my mind I'm starting to assemble a parts list for a bespoke block of relays, but I sure would like this to work as intended. 
Back to Top
Inkara1 View Drop Down
Senior Member
Senior Member
Avatar

Joined: 17-November-2021
Location: Ridgecrest, CA
Status: Offline
Points: 283
Post Options Post Options   Thanks (0) Thanks(0)   Quote Inkara1 Quote  Post ReplyReply Direct Link To This Post Posted: 01-November-2022 at 7:19PM
On mine, the ground wire goes to a ring terminal on one of the large screws that holds on the cover. The screw goes into the metal of the firewall. I replaced the motor, but also found that screw to be a bit rusty, so I hit it with naval jelly and then sanded/filed it the best I could at the backside of the head and along the threads, plus sanded the ring terminal. Just wanted to be sure I had a good ground. It works fine now.

Not sure if yours is grounded the same way. If so, maybe it allows enough current to flow to show voltage on a multimeter, but not enough to get the motor turning.
1972 Gran Torino station wagon, light blue, 351C 2V, prior owner upgraded to 4V (2V heads), originally had a C4 but prior owner changed to C6 for some reason.
Back to Top
Greg73Oregon View Drop Down
Senior Member
Senior Member


Joined: 23-February-2021
Location: Roseville, CA
Status: Offline
Points: 232
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg73Oregon Quote  Post ReplyReply Direct Link To This Post Posted: 02-November-2022 at 5:13AM
If no power to blower, the circuit would be "open", not shorted...a disconnect.
I cleaned up the schematic as best as I could. See attached PDF uploads/6437/Heater_Blower.pdf.
GKF
Back to Top
aquartlow View Drop Down
Senior Member
Senior Member


Joined: 19-December-2011
Location: Summerfield, Fl
Status: Offline
Points: 2271
Post Options Post Options   Thanks (0) Thanks(0)   Quote aquartlow Quote  Post ReplyReply Direct Link To This Post Posted: 02-November-2022 at 9:01AM
The three biggest issues with the resistor is,  1) Corrosion or a poor connection. 2) Bad thermal fuse(check with volt/ohm meter for continuity). The thermal fuse looks similar to a bullet with an electrical lead on each end, Parts Express and MCM(may have been bought out) had these in their inventories at one time, maybe still do. The (3rd) and usually less common issue is the wire coils burning out/breaking, that is easily found and/or seen. Hope this helps.
www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires.

No matter how good she looks, somebody, somewhere, is tired of her sh*t.

Beauty is skin deep, ugliness goes clear to the bone.
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 02-November-2022 at 11:03AM
Thank you all again for the helpful input here. I cannot begin to say how much I've enjoyed having all of your brains to pick.

The plot continues to thicken.

 -  The resistor... resists? I don't know what normal values are, and I may be reading this wrong, but I get 2.5 ohms on low, 1.6 ohms on m1, and 0.1 ohms on m2. This is testing the spade terminals of the resistor directly.

 - The resistor does not have a thermal fuse. It is part DOSZ-18591-A, an example of which can be seen here:
I know those are in short supply, so some worthy fellow better snap that up.

 - Ground is good! With the car off, a line straight from battery hot to blower hot fires things right up.

 - Similarly, a wire strung between battery hot and the feed terminal of the resistor connector (H in that diagram) starts the blower.

So here's the rub. With the car on, a jumper from the LO terminal of the resistor connector to the H terminal should be a direct connection from the battery to the blower via ignition > fuse > blower on/off. Hi on the fan selector switch should be pure battery as well. I'm left with the on/off and the fuse block as sources of the issue.

At the start of all this I verified the condition of the relevant fuse, but the fuse block is all kind of nasty. Maybe a weak connection there? Maybe time to pull the whole control unit, clean up the brake fluid, etc. Regardless, I now believe the issue to be upstream of the Z terminal on what's labeled as the 1975 connector on the diagram.

This'll have to wait for the weekend, at this point. Oh well.
Back to Top
Greg73Oregon View Drop Down
Senior Member
Senior Member


Joined: 23-February-2021
Location: Roseville, CA
Status: Offline
Points: 232
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg73Oregon Quote  Post ReplyReply Direct Link To This Post Posted: 02-November-2022 at 4:14PM
Turn blower switch to Low. Using an ohm meter or a light bulb type continuity checker (with car battery disconnected), disconnect the orange blower motor wire at the connector. Place one probe in the connector (not the orange wire). One by one, connect the other probe to LO and then to H.  If you read continuity at both locations, then the resistor block is OK.
If you don't read continuity, place one probe on H and the other on LO (of the resistor block). You should be able to determine if the resistor block is at fault or the wire or connections in between.



GKF
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 03-November-2022 at 10:57AM
Stole a few more minutes today.

The resistor seems good. At the very least, it's not the problem.

I have the controls with Economy Vent, A/C, Hi-Lo, Heat, ?, and defrost. Not the one with the 4th switch for electric defroster. The wiring diagram looks like it's for the other one, the one with just Heat and Defrost. Not sure how much of a difference that makes. As I understand it, and I could be wrong, with the on/off set to any position other than off I should have the blower turned on. Some settings will also turn on the compressor, temperature not withstanding I guess, but the blower doesn't go through the temp sensor.

I jammed a lead of the multimeter into the fuse block and test for continuity to B on the blower switch connector plug. Continuity was irregular, only happening in a few of the positions. No rhyme or reason, either - I didn't write them down, but it was 50/50 and not split hot vs cold or anything else obvious.

So yup, taking that whole thing apart this weekend, hopefully.

Although, all the vacuum switches seem to work fine. Very tempting to redneck in a separate on/off and move on for now.
Back to Top
handsofstone View Drop Down
Senior Member
Senior Member


Joined: 13-April-2018
Location: Northeast
Status: Offline
Points: 3946
Post Options Post Options   Thanks (0) Thanks(0)   Quote handsofstone Quote  Post ReplyReply Direct Link To This Post Posted: 03-November-2022 at 1:24PM
Have you tried engine off, key on, fan switch on amd wiggled the wires? I woiud try that before disassembly.
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 2:39AM
Success! And man, was it a process.

So I did end up taking the whole climate control unit out of the car. This and putting it back in was probably the hardest part of the whole thing. I took some pictures and I took the whole unit farther apart than was wise or needed, cleaned up all the contacts, put it back together, couldn't get reliable continuity from the mode selection switch in the blower or the AC part of switch. Took the black switch off of the white body, found the problem. The little melted bar in this picture...



...is supposed to hold up the prongs of the switch visible here:



Obviously no good. With that plastic melted down, I wasn't getting good contact between the prongs and the sprung contactors. So I took a soldering iron and a zip tie and added some material to that spot:



Not pretty, but it does the job! From this you can also start to piece together how the switch works - as you move the mode selector this carousel spins, and where the big knobs are the tines are pressed up. The first big knob is the off position. You can kind of imagine, the AC is controlled by the left tine riding on the inner track, and the blower is controlled by the right tine riding on the outer track. One click into economy vent is enough to drop the blower tine but not the AC, another is into AC, then into Hi-Lo where the AC tine is lifted off again, and then after that everything is on all the time. With the melted plastic bracing, the sprung tines were never able to fall far enough to make the contact.

Anyway, back together:



And working flawlessly! Back in the car now, and working great.

Thank you again for all of your help working through this problem. I hope this whole thread is useful to someone down the line!
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 2:45AM
Some miscellaneous other pictures:











(I'd like to say the bottle of acetone moved before the soldering iron was plugged in, but yeah)






Back to Top
Greg73Oregon View Drop Down
Senior Member
Senior Member


Joined: 23-February-2021
Location: Roseville, CA
Status: Offline
Points: 232
Post Options Post Options   Thanks (0) Thanks(0)   Quote Greg73Oregon Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 5:02AM
Thumbs Up Good Job! 
GKF
Back to Top
aquartlow View Drop Down
Senior Member
Senior Member


Joined: 19-December-2011
Location: Summerfield, Fl
Status: Offline
Points: 2271
Post Options Post Options   Thanks (0) Thanks(0)   Quote aquartlow Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 5:55AM
Great work and perseverance in finding the "real" culprit. I had a similar issue years back with that part of the A/C control when the compressor clutch wouldn't engage, I should have brought it up but figured it was too far fetched to be the source of your problem or have you chase dead ends, my mistake. Congratulations on all your efforts as well as the end result.
www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires.

No matter how good she looks, somebody, somewhere, is tired of her sh*t.

Beauty is skin deep, ugliness goes clear to the bone.
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 6072
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 6:02AM
sometimes ya gotta dig a little deeper Thumbs Up
72 GT Ute
   
Back to Top
78FordLtd2 View Drop Down
Member
Member
Avatar

Joined: 19-April-2021
Location: Canada
Status: Offline
Points: 160
Post Options Post Options   Thanks (0) Thanks(0)   Quote 78FordLtd2 Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 6:38AM
Now you're in business! Glad you found the problem! I figured it had something to do with the control box and the contacts not connecting. Elelectrical problems can be a ***** to solve. Glad you didn't resort to tearing your car apart looking for a short! Good find!
Back to Top
derth View Drop Down
New Member
New Member


Joined: 06-October-2022
Location: VA
Status: Offline
Points: 24
Post Options Post Options   Thanks (0) Thanks(0)   Quote derth Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 8:41AM
To be fair, I could have saved a lot of trouble if I had just torn out the whole dashboard, gutted the interior, burned all the tires...
Back to Top
handsofstone View Drop Down
Senior Member
Senior Member


Joined: 13-April-2018
Location: Northeast
Status: Offline
Points: 3946
Post Options Post Options   Thanks (0) Thanks(0)   Quote handsofstone Quote  Post ReplyReply Direct Link To This Post Posted: 06-November-2022 at 3:21PM
Roadkill lives! Zip ties are pretty handy along with epoxy and hot glue. All have their own place in the automotive spectrum.
Back to Top
 Post Reply Post Reply

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.06
Copyright ©2001-2023 Web Wiz Ltd.

This page was generated in 0.078 seconds.