Fuse 10 gets its power directly from the battery. Fuse 11 and 12 get power from the ignition protection relay, which should be powered when the ignition switch is on. Fuse 11 is the wiper power, and fuse 12 is the rear window demister, according to one diagram I have, and go the HVAC in another. Check operation of the ignition protection relay.
Red and purple wires become power and ground when the amplifier commands the motor to move. In one direction red is power and purple is ground, and in the other direction, red is ground and purple is power.

 

Terrific I’ll check this evening. Do I need to remove the dash or is it accessible by removing some trim.
thanks for the tip.

 

Here's a thread in another forum that addresses this issue and the relay location .
https://forums.jag-lovers.com/t/no-a...n-relay/393563

 

Is t

Is this it?

 

Yup that was it Big thanks for everyone's help I had a spare aftermarket and everything is working as it should

 

I was just trying to figure out if that was it. The parts manual shows a rectangular relay, but that might have been a superceded relay.
So your a/c and wiper problems are cured?
That relay takes a pretty good load. You may want to use a 40 amp relay if you haven't already. The contacts may have burned in the bad one.

Jon

 

Yes mine manual showed a square one as well. Yes fixed both problems. !!

 

Great! Glad we could help.

 

I completed this test and am still trying to decide if the servo is bad or it's the mode switch or some other issue. Here's where I'm at:
- disconnected the amplifier
- using the purple, red, and brown wires as explained in the video from the connector on the amplifier (left) side I was able to get the servo to travel all the way to the full hot direction
- then when I tried to switch red/purple to get it going the other way, nothing. Checking voltage at the brown wire shows only around 2v.
- so then I assumed there must be a problem with the servo motor, and proceeded down the instructions to remove it. Those instructions specify to clock it to full cold position using a 9v battery.
- So after disconnecting the servo at its connector on the right side, I gave the 9v battery a shot using only the red/purple connectors, and the motor indeed moved all the way to the full cold position
- That implies the servo is probably OK, doesn't it?
- In another posting someone shows a snipped from a manual or some document that indicated resistance between the red and purple wires should be around 30 ohms, and NO MORE than 100 ohms. However my meter is reading completely open - I have attempted to get a reading a bunch of times and it's always showing an open connection even turning to higher resistance ranges on the meter. I can't find a logical reason for this, but should I just ignore it if the motor seems to be working using the battery?

I think my next test will be to reconnect the round connector on the right, verify if I'm reading only 2v again on the left side, then disconnect the right and see if that voltage reading jumps back up to 12v.
If it makes no difference would that narrow it down to the mode switch?

My electrical diagnosis skills aren't that great as you can tell.

 

When the servo motor reaches the limit of travel in either direction, a limit switch opens and prevents it from being constantly driven against the stops. In this condition, the motor is connected via a diode which will only allow the current to flow in the opposite direction. i.e. it can only be driven away from the limit it has reached. So if it is in full hot mode, it can only then spool towards cool side.

This means that, if using a meter to measure the motor resistance when it is at full travel in either direction, you will see open circuit measuring between P and R if you have red meter lead to red and black meter lead to purple, but correct resistance if you have red meter lead to purple and black meter lead to red. Or vice versa if the servo is at the opposite end of travel.

Make sense?!

It sounds likely that you have a bad microswitch in the mode switch which is causing your voltage drop.

 

Thank you for the explanation - indeed that makes perfect sense. I went out and tried measuring in both directions, still nothing, and then ran the servo with the 9v battery a few seconds such that it was somewhere in-between both stops. Still open in both directions. I wouldn’t expect it to even run at all if it was that bad.

The meter seems fine - I used it to verify resistance from the ambient temp sensor and the temp selector knob.

 

Its a bit odd that you are getting open circuit reading with your multimeter.

However, as the servo spools back and forth with the 9V battery, it must be good. If there were a fault with it which was dragging down the voltage (as you are seeing when connected to the car) then it would also affect the 9V supply and fail to spool.

I still suspect the mode control switch. Seems like its showing 12V on no-load but dropping when the load is connected, which is consistent with a bad microswitch.