I'm dealing with a problem than I think might be common but can't figure out.

When it's cold inside the car (outside temp doesn't matter), the relays will click, the interior lights will flash, and I can't move it out of park (unless I catch it between flashes).

If I turn on the headlights, the clicking/flashing stops and I can take it out of park.

I suspect this is a grounding issue related to the interior fusebox. From my caveman level reading of the wiring diagram, it appears that the fusebox has several ground paths.

Could someone please point me in the right direction? Should I check certain ground points? Where are they located?

Thanks in advance everyone.

 

Interestingly…. This is the exact behavior you get on a 99-02 *if* you code it for DRL (for example w a Nanocom) and do not have the required box/resistor behind the drivers headlamp. I am guessing that since you don’t mention that you’ve coded the DRL’s on, you probably haven’t messed w it and this fault has just popped up?

Questions and this will help us diagnose:

-what year is your truck? 99-02 or 03-04?
- if 99-02 is it perhaps a Canadian market d2?
-did you have daytime running lights activated?

 

It sounds like a bad ground or supply connection. When you turn on headlights, the current (2x55W ~= 10 amps ) seems to weld a connection again.

 

I'd agree it's a bad connection.

However, if by chance OP you have a 1999 which came with the silver DRL resistor box already behind the headlight (Came stock on 1999 in US cars, then they stopped in mid 2000 and it required the missing part be added to enable DRL)

Anyway, if that DRL relay box/connection goes south and it's a 1999, I think you get exactly what he's getting... It's this -- https://www.roversnorth.com/parts/xb...p_discovery_ii

 

It's a 2000. It doesn't have DRLs and I haven't messed with nanocom other than to program new keyfobs.

I had this problem down in Florida with much milder weather and then my mechanic swapped the fuse box. The problem went away above 40 degrees. Now, I am in the midwest, frequently see it below 40 degrees, and the problem has started again.

How can I check the earth points? Are any of them located inside?