A bit hard to see, but corrosion on pin 1 (the lower pin) was making the connection to the ECU intermittent.


The corrosion was on (or I should say "in") the socket...


...and on the plug.


I've no idea how to clean the insides of these holes out.


Jumpering from the wiring harness to test pin 1 corrected the issue, but wasn't sure how to make this a permanent solution.


Then it occured to me to just plug the wiring harness into the test socket! This is working for the moment. Some day (probably not until it breaks again) I'll hunt down a newer connector and replaced the corroded one.

 

The Mk III system as several micro connectors in the wiring on either side of the main HVAC; very tiny pins. I've fixed erratic couple Mk III systems by cleaning the connectors after finding them packed with green gunk

Cheers
DD

 

Green gunk in the little red connectors, I had that too, very difficult to clean them, new connectors were in order.

I think my gunk was caused by a leaking heater matrix.

 

Where did you find the connectors?

One problem with my *fix* is that with the first bank of wires plugged into the diagnostic port, there can be interference from the curved bracket that guides the glove box cover into place. My temporary fix for that was just to remove the offending bracket. Since there is one on each side the glove box still works as required.

Thanks,

John

 

I didn't, I used a generic connector, cut off the old ones both sides of the cable and crimped the new ones on.I spent hours on Google looking for the ECU header but no luck.

You could solder wires to the pins on the PCB then use an connectors on a short lead. fill the connector on the PCB with silicone.

 

That's a thought. Then again, since it's working, and it's hot out, maybe I'll just delay this project until fall.

Thanks,

John

 

Yep I'd do that too, drive it as much as you can.