850 heater problems
 

Greetings from the UK,you lot seem to be very well informed on Volvo prob's. I have a 95 T5 with climate control and it has just started acting up as this list 1) heater fan blows all the time with the switch in any position. 2) seems to be warm/hot wherever the temp controls are 3) distribution switch doesn't seem to alter where the air goes.All this is going on and the warning lights on the climate control panel have never lit up. Any help would be appreciated.

RE: 850 heater problems
 

Greetings back from the UK. Have you read the fault codes for the ECC. If you have an early 1995 model it will be fitted with OBD1 (under the bonnet) Use Socket 1 of module B.

If it is a '95 registered '96 model it will have OBD11 which is situated under the coin holder under the front ash tray. This needs a code reader. Some garages will read the codes free hoping to get a repair job out of it.

RE: 850 heater problems
 

Cheers for that,I'll try that tomorrow, I thought that because the lights hadn't come on , it wasn't an ECU problem

RE: 850 heater problems
 

Hello mate,

Greetings from Yokohama, Japan.

850's climate control diagnostic is not very reliable; sometimes the LEDs blink while other times they don't, even if there is a code in the ECU.

Yes, follow Bill's advice, and if the ACC keeps acting up after resetting the ECU, I would check the following:

1) Blower motor runs at full go, if the resistor is gone. The resistor is noted for failure.

2) Somehow hot coolant is entering the heater core, even when it's not supposed to. This could be due to mechanical failure or electronic control problem.

3) Someone else had the same problem recently, I believe the post is within the first 2-3 pages, see what people said about the problem. It could be one of the damper motors that controls open/close of theflapper doors.

If all else fails, try taking the unit out, blow air duster into the circuit, clean the connections with electrical contact cleaner and re-connect the unit to see if it cures the problem. If this last option fails, you may want to try another unit. It'd be the best if you can borrow someone's, if not you could perhaps find one cheap at eBay or a junkyard.

Cheers,


JPN

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RE: 850 heater problems
 

Hi, thanks for that advice.I have tried to get the fault codes out of socket 1 module B without sucess.When I plug in the fly lead and press the test button the LED lights up and then goes out when I let go, then nothing........... No code flashes at all.Any ideas??? I suppose it must be an ECU problem because all these problems started at the same time.

RE: 850 heater problems
 

Hi,

Did you press the button for approx. 1 second? If pressed for more than 3 seconds, the diagnostic does not respond. I usually try pressing between 1-1.5 seconds, it's kind of hard to tell, though.

Anyway, try again, press the button firmly for about 1 second and then release it to see if the LED starts blinking.

Good luck,


JPN

RE: 850 heater problems
 

Thanks JPN, tried that but still no codes. I'll run it for a while,get it warm and see if that makes any difference, somehow I doubt it!!!! Cheers.

RE: 850 heater problems
 

Hello again mate,

That is strange. It does seem like the problem is in the ECU itself, but not 100% sure.

Refer to this link:

http://www.troublecodes.net/Volvo/

This link is for engine code, but the procedure is the same, the only difference is which socket is used for the fly lead. Now, after you inserted the fly lead, did you turn the ignition switch to "ACC (2nd detent, accessory powered on)"? If you did everything perfect and if the diagnostic LED still didn't respond as it should, flip the module and see back of it to see if there's actually female socket or if it's missing it or if it's loose in the nest.

Moderator Tech will be back shortly, and he would be able to give you better ideas. In the meantime, other experts may also be able to give you better solutions than I could.

Sorry I couldn't help you better.


JPN

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