JF,

Here's a quick test to see if the GP are working:

Turn on the ceiling light and watch it when you turn the key to the GP position. It should dim slightly. If it doesn't, the GP are not working.

First check the fuse in the GP relay. If this OK try extracting and inserting cable plug that goes to the GP a few times. This fixed my '79 300SD when the GP didn't work.

I actually had no problem starting with the temp down to 40F when my GP were not working. I just had to crank for about 5 seconds instead of the usual 1 second when the GP are working correctly.

P E H