dc controller issue

[bgdstang]

has anyone experiaenced a problem with their controller slowly stop working over a few months time. I have the mark VIII with the integral controller on a 93 cobra. It worked flawlessly for a year then slowly I found my self adjusting the temp dial a little lower every few weeks till it was all the way down. Now the fan never kicks on. Brian sent me a new harness with the temp sensor and potentiometer. After swapping it there was no improvement. I've done several diagnostics that he askes me to do to troubleshoot the source of the problem. At this point I can get the fan to run about 30% with the blue AC wire connected to switched ignition 12v source. He then advised me that if I connect both the blue and yellow wires to 12v with the car running the fan should run at 100%.

the car has a ron davis rad and 180 t stat.

any input is greatly appreciated guys,

Brent

[GetMore]

Let's see: How do you know what temperature the engine gets to? (Are you sure of the temp?)
Is there anything blocking coolant flow to the temp sensor?

Have you checked your grounds and other electrical connections?
Maybe there's a shorted wire somewhere?

[bgdstang]

I have a mechanical autometer gauge. When I cruise down the highway the car will run at 175. My friend and I have traced all the wiring twice. The whole car has extra grounds added to it. Brian emailed me and said he would test it if I send the controller to him.


Brent