QuestionQUESTION: Hi wayne,
My mechanic has checked all the fuses to htr and a/c and they are fine but he has no power to pin 21. Pins 20 and 1 are fine. What is causing lack of power to pin 21 and how can it be rectified?
Thank you
ANSWER: DAvid,
There is only three possibilities for lack of continuity in this circuit.
A. No voltage to fuse (was this checked?).
B. Cut or broken wire in circuit. (unlikely unless the wiring is a dogs mess)
C. There is a Junction of 4 wires called A41 or D45 behind the left side of dash according to the wiring diagram but technically you could just rob power off pin 1 as it goes to that union as well. I suspect there is a problem at the junction. The amperage of the circuit is low so just rob power off pin 1. Pin 1 should be Black wire and pin 21 should be green. Not quite sure why they ahve a junction there, kinda strange but I have seen everything.
Wayne
---------- FOLLOW-UP ----------
QUESTION: is it possible that a shorted a/c pressure switch could have caused the a/c amplifier to fry? Is there any way to be positive that the digital amplifier is bad. a new one costs 1176.00 and I can't find a used one.
Answer
CAN BUS TESTER
I sure wish those components were not so expensive. I just put a climate control head in a sebring and it was only 135 bucks. NO need to have a piece like that for 1200.00. Imagine the TV you can buy now for 1200?
Tough call at this point. If I was testing that car and came up with 12V on the two inputs, ground on the other I would be confident in my testing and diagnostic abilities to get one but I am not spending your money nor doing the testing. Did he test the two wires that go to the head for the CAN voltage? The amplifier IS on the Can bus....
Wayne
REVISION
Just for interest sakes I took my scan tool (I have a Snap-On Verus) out to two Siennas I have here right now. They are both 2005 and one has manual AC and the other has automatic AC. The auto system is on the CAN bus and I can get U codes from it. The manual system is not on the CAN bus.
What needs to happen now is the CAN bus circuit needs to be checked to make sure its on the bus. This is the tool I use for this proceedure. Your tech should have one if he is current. (they are about 900.00)
http://s700.photobucket.com/albums/ww10/hammersquash/?action=view¤t=48c088fa.jpg
Open this link in your browser. It is from my photobucket account...
