QuestionQUESTION: Two motors, and Multi-function switch later - they are stilling running all the time. (although the multi-function switch worked for several days, and I thought it was cured). Mechanic has checked all wiring. He's going to see about getting a BCM. Anything else we can check?
ANSWER: Hi Dreama,
I would check to verify that the "on" wiper relay's switch points (30 to 87) are open when you have pulled it out of its socket (to be sure the relay is not stuck closed).
Then I would check (while the relay is out) that the pin socket #85 the inboard pin of the socket), or alternatively pin 7 of the light gray plug at the power distribution box itself, is NOT at ground potential, but rather either has 12V or is "floating" (I am not sure which), when the wiper switch is in the 'off' position. If it were grounded that would be a short circuit that would keep the relay activated even though you had the switch in the 'off' position. That wire (red/violet) goes to pin 73 of the BCM so if it were shorted to ground it would be the same as a failed BCM.
Finally, the motor would continue to run if the wiper self parking function had a poor ground connection. So verify that the black wire from pin 4 of the motor is indeed showing close to 0 ohms resistance to ground. It goes to a 14 pin ground connector (specifically pin 12 of that connector on the left side cowl ground point in the cabin.
The only way for the wipers to not stop is if the relay is either stuck closed, or the actuation coil is grounded continuously, of the self-parking function isn't working properly.
Roland
PS I can't recall your earlier question so excuse me if I am repetitive in my answer. Use the 'thank/rate' tab to get back to me quickly if you have a further question.
---------- FOLLOW-UP ----------
QUESTION: Roland:
Mechanic says he did all this wiring testing very first time I came in (pre first motor), he now recommends BCM replacement. He is even offering free labor because it's been such a problem; but I will still need to pay for parts - New BCM is $700, used one he has found is about $200 (including reprogramming). No guarantees on the used, which way should I go? What's the chance BMC will fix this. I am only having trouble with the wipers, no lights or locks issues at this time.
He can disconnect the couple of wires suggested in an earlier post and wipers will turn on and off, but will not park or do delay. I'm wondering if maybe should just go with that and TRADE.
Advice?
Thanks,
AnswerHi Dreama,
The failure to do the delay function despite the new multi-function switch shows that either the BCM is bad, or that the red/violet wire is shorted to ground as I suggested earlier (or the points of the "on" relay are permanently closed). Now you say that the wiper will turn off by disconnecting wires. Which wires?
The key issue is about the red/violet wire (as I discussed), and of course the parking function (which also is a possible reason for the delay non-function). Is he sure about the ground for the motor?
I assume that you are working with a new motor module so the internal "park" switch is not likely to be the issue. If you are still working with the original module, then a failed park switch could be the cause of what is going on now. Also, the park switch "sensing" wire from the module to the BCM should be verified to be continuous and not shorted to ground. If that were faulty it too would prevent parking. It is dark green/white and connects pin 2 of the motor module to pin 41 of the BCM. So have him check that. I just have the suspicion that it is not the BCM unless all these wire possibilities are checked.
Given the cost, if you have to go BCM I would go used.
Roland
