My check engine light is not working. But if I jump the terminals at the ALDL the fan still kicks in so that means theres no problem or loose wire at the ALDL...right? What else could be at fault? I don't think it's the bulb since my brake light doesn't work either. Is there a ground or some power wire that relates these two. A few of my gagues aren't working either. But I really just gotta get these codes since my car is idling low a stalls after a throttle blip. Any info would be great

 

The MIL gets its power from the GAUGE fuse, and the ECM completes the ground connection to the lamp circuit. I'd find the problem with the dead gauges and lights first.

If you want to test the ECM for stored codes, you can do the same thing with a meter or test light. Supply a 12V supply to one side of the light and ground it at the 'D' terminal on the ALDL:

 

Where is the lamp circuit?

 

Don't outsmart yourself... check the bulbs first.

But if a bunch of stuff in your dash isn't working, either its ground wire may not be hooked up, or the flex circuit on the back of it may be bad, or its connetor damaged.

 

So I should check the back of the ALDL (bulbs too) and then check grounds. Where to these ground to on an 85? Just need someplace to start looking.