AC/Heater Blower fan
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AC/Heater Blower fan
Hey all, I know there are other posts on here about the AC/Heater blower fan, but what I think may be my issue, not 100% that's why I am here, I cant seem to find anywhere. My problem is that the AC/heater fan does not work. I took the control unit out of the das, the farthest I could without unplugging it, checked all connection, everything seemed ok. I read in other posts to check power. So I went out and bought a multimeter to check voltage. I check a brown wire behind the unit, I heard it was the main 12V power for the unit, no power at that cable, so I thought I would check the connector that plugs into the blower fan itself, it is the single connection with the purple and black wire. I measured power their thinking I should get 12V rights, nothing. SO unless I am doing something wrong (Good chance on that) I do not know where to go. If its not getting power, I do not want to go and try to replace the blower cause I doubt the new one will work. Should I check somewhere else for power before I check the actual fan connection? Any one have any suggestions? Oh yeah, it is a 92 Z28.
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Re: AC/Heater Blower fan
Ok, I did a little trouble shooting from another post I found. I created a jumper wire from pin A on the relay to Pin E, which is getting the 12V to pin E, the dark purple wire, which appears to run to the resistor plug, the one that controls the fan speed, and then comes out as a lighter purple wire that appears to lead to the blower fan itself. With it plugged up like that, the jumper wire going from pin a to pin e, I then checked the purple wire that is directly plugged into the blower fan and it was finally getting the 12V. It never got the 12V with the relay attached, however, the fan will still not turn on. So obviously I think one of the issues is the relay, as it is not supply the power to pin e, and the fan is still not power on. Any one have any other suggestions?
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Re: AC/Heater Blower fan
Assuming GM didn't change the blower control wiring between '87 and '92, the attached should help you.
Just look at the SYMPTOM table and do the tests.
I had to convert them to images and chop the pages up to get under the file size limit.
Just look at the SYMPTOM table and do the tests.
I had to convert them to images and chop the pages up to get under the file size limit.
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Re: AC/Heater Blower fan
If there's no power on the brown wire, then there's no power to the ENTIRE system. Nothing will EVER work until you straighten that out.
Follow that wire back up into the dash. About a foot or so in, you'll come upon a connector, of the ABSOLUTE STOOOOOPIDEST DESIGN possible. It violates every common-sense electrical engineering practice it touches. It's too small, not sealed, and uses the plastic connector body to hold tension on the contacts. It is 100% ABSOLUTELY POSITIVELY IRONCLAD TAKE-IT-TO-THE-BANK GUARANTEED to fail, every one of them, in every car that has them (which is pretty much all GM cars through the 80s). I have personally repaired at least 15 of them: at one time, out of the 7 GM cars in my immediate family, 3 of them were without A/C because it had burned up, and I just went ahead and repaired the others as well; out of the other 4, 2 were within hours of failure, and the others were damaged although probably would have last a bit longer.
If you can manage to get it to unplug (that is, if the plastic isn't all melted into one continuous blob), you will find that the contacts are smoked, and the plastic right around them is burnt to ash. That's why your entire A/C system has no power.
The connector in question is called C502 on Paulo's FSM diagrams.
Cut both halves of it off. Strip the wire back about a half-inch, and fold it back over on itself, at the correct length for going into a crimp connector. Install a set of the BIG WIDE THICK HEAVY-DUTY YELLOW slide terminals, preferably insulated. Not the little weenie yellow slide terminals that look exactly like the red & blue sizes; I'm talking BIG THICK WIDE HEAVY-DUTY. If you can't find em insulated, wrap it up real good with electrical tape after you slide them together.
You will find that there is another of those, probably also burned up. (usually is) Start at the blower motor, and locate the purple wire. Follow it about 18" or so to a plug that plugs into a small box. The box is the high-speed relay: in the 3 low speed positions, power for the motor passes through the brown wire, through the blower switch, through the selected part of the resistor assy, to the contact of the relay that's closed when the relay is not powered, and on to the motor. But in high speed, power for the motor DOES NOT come that same path; instead the high-speed contact of the fan switch is wired to the coil of the relay, and when you witch to that speed, the relay operates, sending power from the big fat red wire in that plug you just located, to the motor. Follow that red wire: somewhere about over the right valve cover, you will come to another connector, C112 on the diagrams, of the same unbelievably stoooooooooopid design as the one under the dash, and just as inevitably certain to burn up as the interior one. Replace it as well, with the BIG FAT HEAVY-DUTY slide terminals. Except that one, you don't have to fold the wire back, because it's bigger.
The relay is fine. Always is. Never had to replace one yet. Leave it alone. Fix the wires that bring power to everything.
Follow that wire back up into the dash. About a foot or so in, you'll come upon a connector, of the ABSOLUTE STOOOOOPIDEST DESIGN possible. It violates every common-sense electrical engineering practice it touches. It's too small, not sealed, and uses the plastic connector body to hold tension on the contacts. It is 100% ABSOLUTELY POSITIVELY IRONCLAD TAKE-IT-TO-THE-BANK GUARANTEED to fail, every one of them, in every car that has them (which is pretty much all GM cars through the 80s). I have personally repaired at least 15 of them: at one time, out of the 7 GM cars in my immediate family, 3 of them were without A/C because it had burned up, and I just went ahead and repaired the others as well; out of the other 4, 2 were within hours of failure, and the others were damaged although probably would have last a bit longer.
If you can manage to get it to unplug (that is, if the plastic isn't all melted into one continuous blob), you will find that the contacts are smoked, and the plastic right around them is burnt to ash. That's why your entire A/C system has no power.
The connector in question is called C502 on Paulo's FSM diagrams.
Cut both halves of it off. Strip the wire back about a half-inch, and fold it back over on itself, at the correct length for going into a crimp connector. Install a set of the BIG WIDE THICK HEAVY-DUTY YELLOW slide terminals, preferably insulated. Not the little weenie yellow slide terminals that look exactly like the red & blue sizes; I'm talking BIG THICK WIDE HEAVY-DUTY. If you can't find em insulated, wrap it up real good with electrical tape after you slide them together.
You will find that there is another of those, probably also burned up. (usually is) Start at the blower motor, and locate the purple wire. Follow it about 18" or so to a plug that plugs into a small box. The box is the high-speed relay: in the 3 low speed positions, power for the motor passes through the brown wire, through the blower switch, through the selected part of the resistor assy, to the contact of the relay that's closed when the relay is not powered, and on to the motor. But in high speed, power for the motor DOES NOT come that same path; instead the high-speed contact of the fan switch is wired to the coil of the relay, and when you witch to that speed, the relay operates, sending power from the big fat red wire in that plug you just located, to the motor. Follow that red wire: somewhere about over the right valve cover, you will come to another connector, C112 on the diagrams, of the same unbelievably stoooooooooopid design as the one under the dash, and just as inevitably certain to burn up as the interior one. Replace it as well, with the BIG FAT HEAVY-DUTY slide terminals. Except that one, you don't have to fold the wire back, because it's bigger.
The relay is fine. Always is. Never had to replace one yet. Leave it alone. Fix the wires that bring power to everything.
Last edited by sofakingdom; Jul 13, 2014 at 04:08 PM.
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Re: AC/Heater Blower fan
If there's no power on the brown wire, then there's no power to the ENTIRE system. Nothing will EVER work until you straighten that out.
Follow that wire back up into the dash. About a foot or so in, you'll come upon a connector, of the ABSOLUTE STOOOOOPIDEST DESIGN possible. It violates every common-sense electrical engineering practice it touches. It's too small, not sealed, and uses the plastic connector body to hold tension on the contacts. It is 100% ABSOLUTELY POSITIVELY IRONCLAD TAKE-IT-TO-THE-BANK GUARANTEED to fail, every one of them, in every car that has them (which is pretty much all GM cars through the 80s). I have personally repaired at least 15 of them: at one time, out of the 7 GM cars in my immediate family, 3 of them were without A/C because it had burned up, and I just went ahead and repaired the others as well; out of the other 4, 2 were within hours of failure, and the others were damaged although probably would have last a bit longer.
If you can manage to get it to unplug (that is, if the plastic isn't all melted into one continuous blob), you will find that the contacts are smoked, and the plastic right around them is burnt to ash. That's why your entire A/C system has no power.
The connector in question is called C502 on Paulo's FSM diagrams.
Cut both halves of it off. Strip the wire back about a half-inch, and fold it back over on itself, at the correct length for going into a crimp connector. Install a set of the BIG WIDE THICK HEAVY-DUTY YELLOW slide terminals, preferably insulated. Not the little weenie yellow slide terminals that look exactly like the red & blue sizes; I'm talking BIG THICK WIDE HEAVY-DUTY. If you can't find em insulated, wrap it up real good with electrical tape after you slide them together.
You will find that there is another of those, probably also burned up. (usually is) Start at the blower motor, and locate the purple wire. Follow it about 18" or so to a plug that plugs into a small box. The box is the high-speed relay: in the 3 low speed positions, power for the motor passes through the brown wire, through the blower switch, through the selected part of the resistor assy, to the contact of the relay that's closed when the relay is not powered, and on to the motor. But in high speed, power for the motor DOES NOT come that same path; instead the high-speed contact of the fan switch is wired to the coil of the relay, and when you witch to that speed, the relay operates, sending power from the big fat red wire in that plug you just located, to the motor. Follow that red wire: somewhere about over the right valve cover, you will come to another connector, C112 on the diagrams, of the same unbelievably stoooooooooopid design as the one under the dash, and just as inevitably certain to burn up as the interior one. Replace it as well, with the BIG FAT HEAVY-DUTY slide terminals. Except that one, you don't have to fold the wire back, because it's bigger.
The relay is fine. Always is. Never had to replace one yet. Leave it alone. Fix the wires that bring power to everything.
Follow that wire back up into the dash. About a foot or so in, you'll come upon a connector, of the ABSOLUTE STOOOOOPIDEST DESIGN possible. It violates every common-sense electrical engineering practice it touches. It's too small, not sealed, and uses the plastic connector body to hold tension on the contacts. It is 100% ABSOLUTELY POSITIVELY IRONCLAD TAKE-IT-TO-THE-BANK GUARANTEED to fail, every one of them, in every car that has them (which is pretty much all GM cars through the 80s). I have personally repaired at least 15 of them: at one time, out of the 7 GM cars in my immediate family, 3 of them were without A/C because it had burned up, and I just went ahead and repaired the others as well; out of the other 4, 2 were within hours of failure, and the others were damaged although probably would have last a bit longer.
If you can manage to get it to unplug (that is, if the plastic isn't all melted into one continuous blob), you will find that the contacts are smoked, and the plastic right around them is burnt to ash. That's why your entire A/C system has no power.
The connector in question is called C502 on Paulo's FSM diagrams.
Cut both halves of it off. Strip the wire back about a half-inch, and fold it back over on itself, at the correct length for going into a crimp connector. Install a set of the BIG WIDE THICK HEAVY-DUTY YELLOW slide terminals, preferably insulated. Not the little weenie yellow slide terminals that look exactly like the red & blue sizes; I'm talking BIG THICK WIDE HEAVY-DUTY. If you can't find em insulated, wrap it up real good with electrical tape after you slide them together.
You will find that there is another of those, probably also burned up. (usually is) Start at the blower motor, and locate the purple wire. Follow it about 18" or so to a plug that plugs into a small box. The box is the high-speed relay: in the 3 low speed positions, power for the motor passes through the brown wire, through the blower switch, through the selected part of the resistor assy, to the contact of the relay that's closed when the relay is not powered, and on to the motor. But in high speed, power for the motor DOES NOT come that same path; instead the high-speed contact of the fan switch is wired to the coil of the relay, and when you witch to that speed, the relay operates, sending power from the big fat red wire in that plug you just located, to the motor. Follow that red wire: somewhere about over the right valve cover, you will come to another connector, C112 on the diagrams, of the same unbelievably stoooooooooopid design as the one under the dash, and just as inevitably certain to burn up as the interior one. Replace it as well, with the BIG FAT HEAVY-DUTY slide terminals. Except that one, you don't have to fold the wire back, because it's bigger.
The relay is fine. Always is. Never had to replace one yet. Leave it alone. Fix the wires that bring power to everything.
Are these the connectors you are talking about. If they are the one in the engine was right by the distributor cap. If this is all it is, I will save the money on the blower fan. I did replace the relay and it did get me the voltage back to the blower fan, before I did not have any. Either way only cost me 12 bucks from autozone. I will look at those wires when I get back into town or if I have time in the morning before I leave. Thanks. The pic of my Camaro is with the aftermarket rims I got when I picked it up, I also have the originals which are currently on.
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Re: AC/Heater Blower fan
Yup, those are they. Considering that the dist cap is right next to the pass side valve cover, that's right where that one is expected to be.
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Re: AC/Heater Blower fan
Ok, now what. Took care of those wires. Disconnected battery before I did of course, but now just about everything I touch hat metal in my car I get shocked. Noticed it first after the battery was already disconnected. Would touch, what I think is the AC Compressor and kept getting shocked. Got everything buttoned up with the two wires, hooked up battery, still got shocked. I even got shocked when I would touch the gear shifter inside the car. I have no idea what is going on. OH YEAH, AC Heater fan still does not work. That is irrelavent to the current issue I just ran into
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