QuestionQUESTION: Hello Roland,
So when I start my car the idle seem to go up and when it does the engine fan comes on as does the A/C compressor. I can hear relays clicking when the fan and compressor kicks on and off. Now here is the thing, they go on for a few seconds then they shut off for a few seconds and then they go on for a few seconds and then off. It does this the whole time the car is idling even at a cold start. I'm not sure if it is dong it through the driving range. This car has gone through a few computers and I am wondering if I need to replace yet another computer. The other thing is that the overhead dash is always resetting itself and according to it, it is always 55 degrees celsius even when it is freezing cold.
Any help is appreciated. Thank You
-Ron
ANSWER: Hi Ron,
The fan/compressor operation is associated with either asking for AC or asking for windshield defrost. I am wondering whether there is a flakey switch on your heater/ac controller that is giving a false request for either of those two settings? I don't know what car model you are describing so I can't reference any specific wiring diagrams to give you a suggestion on some electric troubleshooting strategies, so let me know that please and maybe we can go further.
The overhead dash appears to have a self-test mode which you might try. With the ignition off, press and hold the US/M button and the step button and while holding turn the ignition to the run position. The segments will all be tested and then it will display either pass/fail/or CCD. Let me know the result and we can again go further. I would suspect the temp sensor or its wiring is at fault (55C is the max reading it can show), so let me know the model of car you have there for specific suggestions.
While the body control module is involved with both these control systems I would not suspect it alone is the cause.
Roland
---------- FOLLOW-UP ----------
QUESTION: Hello again,
It is a Landau model 1988. Based on some of the things you told me I went back out and the car seemed to only do that when I had the ATC on defrost setting or A/C setting. The A/C doesn't work as it needs recharging. Whenever I had it on Panel or Floor, no problems with the engine fan comming on. One other problem, the blower for the hvac never turns off, for the longest time it ran on high whether the ATC was on or not. Now it runs on low whether it's on or not. When it is cold out the L.E.D bounces all around until things warm up.
As for the overhead display, I don't have a Step button in this model. If it helps I think this is a Canadian model. Although it did give me the option to have a voice in the car but as soon as it enabled, it disabled. Possibly not hooked up? Or unavailable.
Anyways Thanks for your quick response.
AnswerHi Ron,
You are welcome.
On the AC/fan-compressor, I believe this is happening because you don't have sufficient refrigerant in the AC system.
On the blower of the AC/heater, the power/vacuum module on the lower right front of the unit (5 or 6-sided shape) under the dash is the site of the multiple voltages for the blower. It has some solid state components and capacitors that are subject to electronic failure. If you removed the module and looked at the circut board that supplies the black/tan wire that goes to the blower you might find a component that is looking strange, and if you could find a replacement and solder it in on the board you might be able to restore the multiple fan speeds.
On the temp display I would check the wires to the sensor and the plug at the sensor which is located on the hood latch support strut in front of the radiator.
I'm still looking for the electronic voice system. I am not certain it is in the car.
Roland
