A/C and Heater problems
Advanced
Joined: Mar 2005
Posts: 71
Likes: 0
From: Orlando Florida
That might have been what happened with mine. When the foam got in the way of the door's operation, it might have messed up the linkage or motor somehow. So the idea is removing the carpeting in the passenger side to get to the motor and linkage? Because like I said, I've been down there and when I pulled the carpet out a little, there was just like a rubber looking padding behind it. Am I missing something here? BTW, Gregg...did yours start acting up with or without the trouble code?
Well, I was able to pull the carpet away and find where the actuator motor is that controls the door. Now how on earth do you pull the bottom part of the dash out without breaking something? It doesn't appear to just pull out easily, plus there are no screws or bolts. Any ideas?
Well, I was able to pull the carpet away and find where the actuator motor is that controls the door. Now how on earth do you pull the bottom part of the dash out without breaking something? It doesn't appear to just pull out easily, plus there are no screws or bolts. Any ideas?
Last edited by brosain; Jan 21, 2006 at 12:45 AM.
Burning Brakes
Joined: Nov 2005
Posts: 1,211
Likes: 2
From: Dumas Arkansas
Originally Posted by SunCr
"Still wish someone would say what this bugger does"
It's the Blower Module. Through '89 it provides a ground for the compressor clutch and controls Blower Speed. For '90 and above, it only controls Blower Speed. The Blower signal comes in on the Brown Wire. About 2.5 volts at "1"; 6 or so volts at "10". Output is Purple (or whatever color is hot at the Blower). "1" should have an output of 4 volts; "10", 12 volts. If the Blower Speed is wrong, troubleshoot the voltages first. If the voltages are correct, it's probably leaking air somewhere. Duct work is sealed with foam and that deterioates with age. Drop the passenger's hush panel and if you have air blowing on the floor, you need to take apart the dash and seal it back up (duct tape works as well as anything).
There is a cooling tube from the blower housing to the motor. Make sure it's hooked up and not allowing air to blow into the engine compartment. Feel for air all around the Evaporator Housing, especially where it splits, underneath it, and where the lines enter and exit. If you can feel air, seal it up with some window ribbon sealer (a sticky, clay like substance easily molded and impervious to water).
All Years monitor actual Blower Voltage (Speed). The output signal is spliced and returned to the Control Panel (through '89) or the Programmer ('90 and up). That return voltage is protected by a 5 amp fuse (on the Firewall through '89); in the fuse box ('90 and up). Should the fuse open, the Blower will default to max speed and may run with the ignition off. If you have these symptoms, check the 5 amp fuse.
Blower Motors can draw a lot of amps - 25 if they're worn. That creates heat and is why the Module is in the air stream and has a large heat sink. Blower wiring is usually 16 gage - marginal for a high draw. Check the terminals at the Blower Motor for discoloration. If there, remove the terminals from the weatherpak connector and solder them to the wires. That should stop the voltage drop and keep the blower at max speed when requested.
It's the Blower Module. Through '89 it provides a ground for the compressor clutch and controls Blower Speed. For '90 and above, it only controls Blower Speed. The Blower signal comes in on the Brown Wire. About 2.5 volts at "1"; 6 or so volts at "10". Output is Purple (or whatever color is hot at the Blower). "1" should have an output of 4 volts; "10", 12 volts. If the Blower Speed is wrong, troubleshoot the voltages first. If the voltages are correct, it's probably leaking air somewhere. Duct work is sealed with foam and that deterioates with age. Drop the passenger's hush panel and if you have air blowing on the floor, you need to take apart the dash and seal it back up (duct tape works as well as anything).
There is a cooling tube from the blower housing to the motor. Make sure it's hooked up and not allowing air to blow into the engine compartment. Feel for air all around the Evaporator Housing, especially where it splits, underneath it, and where the lines enter and exit. If you can feel air, seal it up with some window ribbon sealer (a sticky, clay like substance easily molded and impervious to water).
All Years monitor actual Blower Voltage (Speed). The output signal is spliced and returned to the Control Panel (through '89) or the Programmer ('90 and up). That return voltage is protected by a 5 amp fuse (on the Firewall through '89); in the fuse box ('90 and up). Should the fuse open, the Blower will default to max speed and may run with the ignition off. If you have these symptoms, check the 5 amp fuse.
Blower Motors can draw a lot of amps - 25 if they're worn. That creates heat and is why the Module is in the air stream and has a large heat sink. Blower wiring is usually 16 gage - marginal for a high draw. Check the terminals at the Blower Motor for discoloration. If there, remove the terminals from the weatherpak connector and solder them to the wires. That should stop the voltage drop and keep the blower at max speed when requested.
I had said last night that after I took the 3 screws out to look down to the door and then replaced the module the air started working ok but not great. Tonight when I was driving back the problem came back. You'd turn the air on and after 20 seconds there was the burning smell again. Also, when I turn the air on the fan speed is always on 0. Is this normal? I have to turn it to 5 everytime I turn it on. It's a 92. I hope the new module tomorrow does the trick. If not then it's time to go see the man.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Originally Posted by brosain
BTW, Gregg...did yours start acting up with or without the trouble code?
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Fan speed - Auto 60 or 90 - should be "10". In between, fan speed is determined by the setting and the signals from the inside and outside temp sensors. The only time you should see the "0" is if power has been removed and then as the Programmer goes through a relearn procedure, nothing works - compressor, blower motor, etc - until it's reestablished some memory - takes 30 seconds to a couple of minutes. A quick test would be to put it at 72 and then let it roast in the sun for an hour or two. When you turn it on, the fan should be at max (10), but then diminish as the car cools down (mine seems to like 4, but I've ridden in some Caddys that seem to be happiest at a 6 or 7). With the odor, it's logical to replace the module, though it could still be something else - like the Programmer - which on the later Years, seem to be nearly as problematical as the Module. I'm guessing that it's because so much more processing is built into it. Who knows.
Advanced
Joined: Mar 2003
Posts: 73
Likes: 0
From: Home for 2 months
Having replaced a blower motor fuse, now the blower motor runs but I get no air flow. This is the second fuse I has to replace since my son jumped the car two weeks ago. Is there a fuse for the air flow control???
Thanks
Thanks
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
What Year - through '89, there is no Blower Motor Fuse as with Electronic Air, the Blower Module is powered up by a fusible link. Compressor Clutch, which gets it's ground at the Module (through '89), is protected by a 25 amp fuse, but that doesn't effect Blower Operation or the Temperature Door. Temp Door motor gets it's power from an ignition source, but it depends on the year. If all you have is defrost, for any Year, then the vacuum source may have gotten broken when you (or someone) jump started it. Use the vacuum line diagram to find it. It passes through a plastic check valve (usually near the distributor or the left side of the firewall, though on the LT motors it's under the rail cover. Anyway, with age, they get pretty brittle and it's easy to break one.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Originally Posted by SunCr
What Year - through '89, there is no Blower Motor Fuse as with Electronic Air, the Blower Module is powered up by a fusible link. Compressor Clutch, which gets it's ground at the Module (through '89), is protected by a 25 amp fuse, but that doesn't effect Blower Operation or the Temperature Door. Temp Door motor gets it's power from an ignition source, but it depends on the year. If all you have is defrost, for any Year, then the vacuum source may have gotten broken when you (or someone) jump started it. Use the vacuum line diagram to find it. It passes through a plastic check valve (usually near the distributor or the left side of the firewall, though on the LT motors it's under the rail cover. Anyway, with age, they get pretty brittle and it's easy to break one.
Burning Brakes
Joined: Nov 2005
Posts: 1,211
Likes: 2
From: Dumas Arkansas
Well I had an unreal experience today. I went to the local store this morning to pick up the new blower module acdelco part #71642. The box said part #71642 so I paid the man with a Benjamin and went outside to install it. I disconnect the neg battery took the 3 screws out of the blower module disconnect the 2 clips. Next I noticed the part seemed to be the same except the 2 clips on top of the module were REVERSED. Where as the small clip was at the front big at the back. It supposed to be big on front of the car and small facing rear.
So I didn't know any better not ever doing it before and just turned the 2 clips or what ever it's called and hooked it up. Then I put the screws back in and tightend up the battery and left.
Well I get about a mile down the road still no air and noticed smoke starting to form outside the windshield then it started coming thru the vents heavy. It was so bad I had to pull up on the concrete imbankment/median. I knew fire had to be close.
I was scared like a mf. After I got the car up there scraping the bottom pretty good but at the time it didn't matter turned the car off and took the screws out and yanked the new module out and installed the old one and went on. I didn't disconnece the battery because I forgot.
Went back to the delco place and told Larry this part aint working. He looked it up in the book and noticed it was the wrong part. Right part # on the box but wrong module. The module I had was for another model Vette. It's been over 12 hours and you can still smell the smoke pretty bad. My luck the new part when it comes in next week probably want even fix my original problem. Oh well I guess next time I'll take more time and make sure there exactly the same.
So I didn't know any better not ever doing it before and just turned the 2 clips or what ever it's called and hooked it up. Then I put the screws back in and tightend up the battery and left.
Well I get about a mile down the road still no air and noticed smoke starting to form outside the windshield then it started coming thru the vents heavy. It was so bad I had to pull up on the concrete imbankment/median. I knew fire had to be close.
I was scared like a mf. After I got the car up there scraping the bottom pretty good but at the time it didn't matter turned the car off and took the screws out and yanked the new module out and installed the old one and went on. I didn't disconnece the battery because I forgot. Went back to the delco place and told Larry this part aint working. He looked it up in the book and noticed it was the wrong part. Right part # on the box but wrong module. The module I had was for another model Vette. It's been over 12 hours and you can still smell the smoke pretty bad. My luck the new part when it comes in next week probably want even fix my original problem. Oh well I guess next time I'll take more time and make sure there exactly the same.
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Burning Brakes
Joined: Nov 2005
Posts: 1,211
Likes: 2
From: Dumas Arkansas
Well now the part store said the blower module is BACKORDERED and could take up to a month for GM to make a new one. Wow, it took 2 weeks to find this out. He said he'd give me a refund but acdelco nationwide is out of this part#15-71642.
Thankfully it's not Summer yet.
Thankfully it's not Summer yet.
