Originally Posted by CL770

Hi, I've been reading this forum for a while but this is my first post. I hope other forum members find it useful because I'm sure this is a common problem (and a simple fix).

One of the niggling issues I've had with my Crossfire is the erratic fan speed control for the climate control. Fist up I replaced the resistor unit on the fan, that didn't change anything (a waste of time). I've replace the climate controller twice now without much success, as they both eventually failed. I purchased another unit from the wreckers last week, I went to install it today and it was faulty as well. So I finally made the effort to try and work out what was failing.

I've pulled a unit apart before and couldn't identify any obvious faults (dry joints, failed components etc), but today when I pulled another one apart I noticed something entirely different. This time when I removed the front of the unit, the rear (horizontal) circuit board came out still attached to the front (vertical) circuit board with the controls on it.

The main issue I identified was the very poor contact provided by the 18 pin header and socket that attach the two boards electrically. When mounted in its case, the two circuit boards attach very loosely. When the unit is new, the contact is probably ok, but after you start to use the controls and drive the car around I bet the contact deteriorates over time and gets erratic. I've taken some pictures that show the issues, there are two main ones:

1. The front RHS of the rear circuit board hits part of the plastic souround of the front board mounting, stopping it from fully pushing into the header socket. Fix - file some of the plastic away. Push the rear circuit board all the way into the header and apply some epoxy glue to hold it there.

2. There's a small locating pin at the rear of the external housing that locates the circuit board. Fix - cut it off with a Stanley knife, as it pulls the rear circuit board away from the front board when you mount it in the housing. You could also apply some more epoxy here once you put it all back together.

If you fix both the issues above you will get much better electrical contact between the front and rear circuit boards through the header and pins. I modified all three of my faulty units today, they now all work like new. I guess the wreckers won't be selling me any more climate control units.

PS. I wonder if this has also been the cause of my intermittent rear demister issue as it's also controlled through this header?

I hope this helps someone.