HVAC Actuator/IPM Module Problem?
Hi guys... I have an '02 Deville. Been having the clicking at startup like others describe, alwalys knew it was a gear slipping somewhere. Had to fix the blower so I decided that while I was in there I would fix the click... tired of only having air in the floor...
In doing some troubleshooting and disassembly, I confirmed the problem with the actuator, one of the teeth on a gear is gone. Fine.
I notice however that during the testing, I do not see any movement out of the Drivers temp actuator or the Passengers temp actuator. Run the system, temp knob all the way to 60 deg, no movement, knob to 90 deg, no movement, pass temp only adjusted, no movement. At this point, the recirc actuator was still working because I could hear the difference when going between defrost and any other mode without defrost.
I look at the wiring diagrams and start probing wires. The output to the mode actuator is going + 9V, 0, -9V and repeat.. over and over with about a second and a half between pulses. Same on the drivers temp output. Did not check the passenger temp but I suspect the same thing.
So, I take the mode and driver temp actuators out, hook them to the battery and they run beautifully, Swap polarity and they run the other way. No problem.
So, Now I'm thinking my problem is the HVAC control a.k.a Instrument Panel Integration Module (IPM).
I know I need to replace the mode actuator but I'm thinking the output from the DIM should be a sustained positive or negative voltage depending on which way the motor needs to run. There is no feedback circuit from these actuators so their position must be determined simply by the IPM knowing how long to run the actuator to get it to a certain position.
Hopefully someone has some info on the correct signals I should be seeing out of the IPM so I can confirm my findings or give me some reason why these actuators are not running.
Oh yea, I have had the IPM B0429 code forever but the system still worked, always got the clicking out of the mode actuator. The only thing I noticed is that I had no fidelity in the auto temp circuit. In the winter, I would move the temp hotter, it would get hotter for a time, then get cooler, I would move it up some more, it would be hot then get cooler again, finally I would have to put it on 90 which seems like it made the actuator go wide open hot. Then I would have to turn it back down and repeat the cycle to keep the temp comfortable in the car.
Maybe that problem was in the IPM? Who knows.....
Right now, the car is tore down to the firewall practically, steering column laying on the seat, etc. I'm not in to standing on my head... So, I need to fix this ASAP cause I need to drive it......
Thanks to all for the help.
Larry
Hi guys... I have an '02 Deville. Been having the clicking at startup like others describe, alwalys knew it was a gear slipping somewhere. Had to fix the blower so I decided that while I was in there I would fix the click... tired of only having air in the floor...
In doing some troubleshooting and disassembly, I confirmed the problem with the actuator, one of the teeth on a gear is gone. Fine.
I notice however that during the testing, I do not see any movement out of the Drivers temp actuator or the Passengers temp actuator. Run the system, temp knob all the way to 60 deg, no movement, knob to 90 deg, no movement, pass temp only adjusted, no movement. At this point, the recirc actuator was still working because I could hear the difference when going between defrost and any other mode without defrost.
I look at the wiring diagrams and start probing wires. The output to the mode actuator is going + 9V, 0, -9V and repeat.. over and over with about a second and a half between pulses. Same on the drivers temp output. Did not check the passenger temp but I suspect the same thing.
So, I take the mode and driver temp actuators out, hook them to the battery and they run beautifully, Swap polarity and they run the other way. No problem.
So, Now I'm thinking my problem is the HVAC control a.k.a Instrument Panel Integration Module (IPM).
I know I need to replace the mode actuator but I'm thinking the output from the DIM should be a sustained positive or negative voltage depending on which way the motor needs to run. There is no feedback circuit from these actuators so their position must be determined simply by the IPM knowing how long to run the actuator to get it to a certain position.
Hopefully someone has some info on the correct signals I should be seeing out of the IPM so I can confirm my findings or give me some reason why these actuators are not running.
Oh yea, I have had the IPM B0429 code forever but the system still worked, always got the clicking out of the mode actuator. The only thing I noticed is that I had no fidelity in the auto temp circuit. In the winter, I would move the temp hotter, it would get hotter for a time, then get cooler, I would move it up some more, it would be hot then get cooler again, finally I would have to put it on 90 which seems like it made the actuator go wide open hot. Then I would have to turn it back down and repeat the cycle to keep the temp comfortable in the car.
Maybe that problem was in the IPM? Who knows.....
Right now, the car is tore down to the firewall practically, steering column laying on the seat, etc. I'm not in to standing on my head... So, I need to fix this ASAP cause I need to drive it......
Thanks to all for the help.
Larry
