Cargo light stays on.....any ideas
 

So suddenly my cargo lite won't turn off on my 98. It goes out when the doors are open, but as soon as then interior light goes out, the cargo light comes on. So I don't think it's door switches. It works normally when the door is open and I turn on the cargo light switch. Any suggestions???

Re: Cargo light stays on.....any ideas
 

ttt

Re: Cargo light stays on.....any ideas
 

You would have to have problems with 2 different circuits for that to occur. The interior lighting and the cargo lamp gets ground from a smart module called the interior lamp control module. It's under the center of the dash below about where the radio lines up. It has 5 wires going to it in a straight line connection. A pink wire is on one end and a white wire is on the other end of the connector.

So if this module were defective, it would lets say be putting ground on the lighting circuit. But that in it self would not light the cargo light.

The cargo light still has to be getting power from the other circuit. That of course is where the switch comes in to play. So could both circuits be defective????? I highly doubt it.

Then there's the brainstorm of some dumb ass engineer (I can say that cause I are one). That brainstorm is to not allow the cargo lamp to come on unless the interior lights is on. So this means even if the module is defective, and the supply circuit is shorted past the switch, the interior lights should still be on.

I don't think there are broken wires or wires rubbing against each other cause there are 2 circuits involved that are opposite.

This leaves me to conclude one thing. At some point in this trucks life, someone did some Rube Goldberg wiring job. Perhaps to bypass the interior lights to allow the cargo lamp to come on without the interior lights (the way I think they should work in the first place). And now that botched wiring job has gone wrong.

I could possibly lead you to points along the wiring to measure to try to find the problem.

The first thing to do is find the interior lamp control module and pull the connector off to see if the light turns off. If it does, you need to check the grey wire going to the ILCM for ground. With the doors closed, if the grey wire is grounded when you unplugged it then the grey wire is touching ground. If the grey wire has a high resistance, the module is defective. Doors must be closed to check the grey wire condition.