Pacs Legend

Vehicle - 1998 A6q 2.8 sedan with the solar sunroof. How would I be able to distinguish where my problem lies either with a bad solar relay(#385 part #4B0959589)or blower motor resistor?

When I turn my heating/cooling on the fan rarely functions, once in a blue moon it will start working again and soon quit. I know the compressor is engaging, so I have narrowed the problem down to either the solar relay or blower motor resistor. Could someone please point me in the right direction of which terminals to test on the relay #385 part #4B0959589, as they are only marked 1-6 and I am unable to identify which terminals to hook up to the multimeter and which ones to hook to the battery?

Also if it turns out my relay is functioning, is the blower motor resistor located under the glovebox? Any special instructions associated with testing/replacing the blower motor resistor? If I am approaching this problem completely incorrectly please advise.

TIA, Mark

mpw

I copied this from a post several years ago, when I thought I might have a problem with the separation relay. The post didn't quite match what I saw on the wiring diagrams, so I noted the difference in parentheses. I haven't pulled up the wiring diagram to check this again, but perhaps it will be of some help.


OK, The separation relay is between fuse #25 (key on B+) and the blower.*

The exact working of the relay is not explained, but terminal #4(7) (bk/grn) goes to the bower motor, fuse #25 (key on B+) comes into the relay at terminal #5(4)(bk/bl). If you jump between #4(7) and #5(4) the blower should function. The solar panel B+ comes in at terminal #6(2)(rd/bl). The relay switches between the #5(4) (fuse #25) and #6(2) (solar panel B+) dependent on if the vehicle is running or not. Terminal #2(3)(rd/bl) is B+ all the time from fuse #10(15) and #1(6)(brn) is ground all the time so I assume that only leaves terminal #8(5)(vio/gray)to be the switching signal from the climate control head.*

To test it check;*

#2(3)- B+ all the time from fuse #10.*


#1(6) - ground all the time*

#5(4) - B+ key on from fuse #25*

#4(7) - jump #4(7) to #5(4), key on, blower should function*

#6(2) - jump #4(7) to #6(2) key off the blower should function if the solar cell is in the sun and roof is closed.*

#8(5) - check for voltage key on and key off = should switch between a voltage signal and not (or vise versa) ( I don't think so).*

If all these tests are as described the relay has likely failed.*

That should do it. Let me know how it turns out.*

Thank You!*
Jake*

Pacs Legend

Jake,

I am somewhat confused. I would like to just take the relay out and test with a 12v power supply checking continuity between terminal leads. I should probably be able to figure it out with the information you have provided but unfortunately I have not.

Each terminal is identified with a #1-6 as you know, my question is what number terminals should I check continuity between and which number terminals should I connect the power supply to?

Mark