Bad outside mirror switch?
09-27-2007, 05:00 PM
#16
Instructor
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Join Date: Dec 2005
Location: Silver Spring, MD
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Alan:
Here's what I found today:
1. With jumpers in the floor connector ( #1 to 12, and 2 to 14), at mirror control switch (5 pins), I get 12 v between pin #2 and #4 (gnd) per your test.
2. At the Mirror Control Unit, I observed the printing on the outside as you suggested, but it didn't mean a lot to me and the wiring diagram is hopeless. I removed all three plugs at the MCU. At the big 14-pin plug I could not find any red/white wire suggesting 12v in. I did, however, find red/wh and brn on the innermost of the two 5-pin plugs. I did not get any volts between the red/wh and brn leads there (The plug does not have numbers on the pin locations.) The other, left-most, plug does not have a red/wh lead.
So, to my mind the MCU can't work if it's not getting power. And, I'm assuming that middle 5-pin plug is the power source, but I can't verify it on the wiring diagram. I haven't bothered to test the other connections between the switches and motors, feeling that it's best to get power first and then go from there.
Anything stand out to you?
Bob
Here's what I found today:
1. With jumpers in the floor connector ( #1 to 12, and 2 to 14), at mirror control switch (5 pins), I get 12 v between pin #2 and #4 (gnd) per your test.
2. At the Mirror Control Unit, I observed the printing on the outside as you suggested, but it didn't mean a lot to me and the wiring diagram is hopeless. I removed all three plugs at the MCU. At the big 14-pin plug I could not find any red/white wire suggesting 12v in. I did, however, find red/wh and brn on the innermost of the two 5-pin plugs. I did not get any volts between the red/wh and brn leads there (The plug does not have numbers on the pin locations.) The other, left-most, plug does not have a red/wh lead.
So, to my mind the MCU can't work if it's not getting power. And, I'm assuming that middle 5-pin plug is the power source, but I can't verify it on the wiring diagram. I haven't bothered to test the other connections between the switches and motors, feeling that it's best to get power first and then go from there.
Anything stand out to you?
Bob
01-15-2019, 06:26 PM
#18
Three Wheelin'
Alan and rmr25, I know this post is old... I am having some issues as well with my GTS and having a hard time figuring what it could be. I completed your response Alan (#11) and no function at the mirrors. I am about to tackle your suggestion in post #15 but was curious if you or rmr25 remembered what had happened after his last response and your's... It's been over 10 years but this has been very helpful as i figure out what it could be. Thanks for any help insight as I sort this issue out.
01-17-2019, 06:15 PM
#19
I followed the post #11 suggestion of taking the seat module out of the equation by jumping the pins on the 14 pin connector. Both mirrors still completely dead but with the pins jumped you then have power and ground into the mirror circuit which should make debugging it much easier.
For what it’s worth in my case I seem to remember that I had to strip down both the change over switch and the mirror control toggle to clean the connections inside. That restored some mirror functions and then I had to take both mirrors apart to clean the connections inside them. Hopefully you’ll have the same luck and it will just be a bad connection somewhere.
I’ve had lots of electrical issues with my S4 but then it was off the road for more than 10 years. Early on I bought a power probe III which makes this sort of job much easier.
Duncan
For what it’s worth in my case I seem to remember that I had to strip down both the change over switch and the mirror control toggle to clean the connections inside. That restored some mirror functions and then I had to take both mirrors apart to clean the connections inside them. Hopefully you’ll have the same luck and it will just be a bad connection somewhere.
I’ve had lots of electrical issues with my S4 but then it was off the road for more than 10 years. Early on I bought a power probe III which makes this sort of job much easier.
Duncan
01-17-2019, 06:26 PM
#20
Three Wheelin'
Duncan, thank you! I do have power into the 5 prong switch (the toggle one) as well as ground, I've had this all along even before bridging the 14pin under the seat and all of my memory functions worked, just nothing from the mirrors. I did take that one a part and cleaned it inside even though it looked good it may have needed it. I haven't taken the other one apart (the switch from left to right mirror) yet and will do that!
After that I'm guessing it's off to taking Mirror glass off and looking at those connections as well. I want to do this prior to dismantling the wiring all together. If you have anything additional I'm all ears. In the meantime I'll get to work on those next items.
Thanks,
Bryan
After that I'm guessing it's off to taking Mirror glass off and looking at those connections as well. I want to do this prior to dismantling the wiring all together. If you have anything additional I'm all ears. In the meantime I'll get to work on those next items.
Thanks,
Bryan
Last edited by x98boardwell; 01-17-2019 at 06:28 PM. Reason: added text
01-17-2019, 07:21 PM
#21
On the wiring diagram in the workshop manual for my S4 it shows you how the connections are made inside that mirror control toggle. When I put it back together I tested it with a multi meter to check that there was continuity between the relevant pins when you move the toggle around. Pretty sure I had it apart to clean inside twice before I got it working despite it looking perfectly clean.
By the way, looking at the wiring diagram for my S4 power to the adjustment switch comes straight from the fuse board but power to the mirror control module comes via the seat module if you have memory function. That would explain why you saw power at the switch before. Jumping the 14 pin connector should give you power to pin 30 on the mirror module - that’s presumably where the power for the mirror motors is coming from.
If both mirrors are dead I’d hope that it was something common rather than multiple problems.
Duncan
By the way, looking at the wiring diagram for my S4 power to the adjustment switch comes straight from the fuse board but power to the mirror control module comes via the seat module if you have memory function. That would explain why you saw power at the switch before. Jumping the 14 pin connector should give you power to pin 30 on the mirror module - that’s presumably where the power for the mirror motors is coming from.
If both mirrors are dead I’d hope that it was something common rather than multiple problems.
Duncan
02-17-2019, 03:28 PM
#22
Three Wheelin'
Duncan, thanks for responding. I started a new thread to help diagnose everything. I will be checking power to all fuses behind CE panel to confirm nothing has gone bad.
