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View Full Version : Could it be a loose wire? heater/AC related problem



keystone
03-15-2005, 01:23 AM
Here is the problem:
After starting the car, I cannot control the heating or cooling. When I turn the rotary dials (both driver and passanger) it does not make any difference. When I push the AC switch, light comes on, but AC does not work. The light on the air circulation button comes out but I don't hear any vent closing sound. When I push the rear defogger switch, nothing, no light. After driving the car about 20-30 minutes (when the car is really hot), suddenly everything starts working; I hear some noise (like a vent closes or something), then I know things work. AC, rotary dials, air circulation (it closes and opens some vents with a loud noise), and rear defrost switch with the light. I think I have a bad heater valve, because the passanger side heat is just warm, does not get hot like the driver side when things start working.
I think I have some connection problem as well, or at least I suspect. It seems like, when the car is really warmed up, somewhere, somewire makes the connection, but I am not sure where or if this is the case. Has anyone had the similar problem? Before replacing heater valve, aux. water pump etc, can you tell me where the good place is to check for wires? I changed all the fuses related to heating/cooling. I did a search and read everything related to heater valve, but I think something else is going on, since everything suddenly starts working after driving the car a little. Thanks. By the way, car is '95 525

shogun
03-15-2005, 01:55 AM
A good place to check for the wire connections: Looks like it is somehow temperature related. So when the electronic gadgets warm up. it works, that seems to put aging capacitors into the possible things to check.
As far as I know (read) there is one (?) capacitor also in the control module for the IHKA. This one sits behind the Microfilter and has on each side 2 plugs. So you have to remove it by opening both side panels of the center console.
Resolder every soldering point and look for that capacitor.
Next item would be the sword. But the sword is basically only responsible for the fan speed and has nothing to do with the control. So go first for the control module, also spray the contacts on each side with electr. contact spray. Maybe even that might solve the problem already. Sometimes these plugs are also removed by mistake when someone changes the filter.
Clean the temp sensors too inside the cabin.