Hey all I am new here and just bought my new to me 88 W100 the truck is driving and running great but the check engine light came on when i was test driving it. the light goes off when you push the brake in. i have tried the key on and off a couple times to make it blink my code out but it never blinks. any ideas?

 

http://www.allpar.com/fix/80s-codes.html

You should get a 55 code even if there are no codes.

 

That's what I have read as well but it just doesn't do anything. No telling what people have done with this thing before I got it. Maybe it's hooked some way to the brake now IDK need to do some digging.

 

Does the light come on when you first turn the key on? If so then it's working. Try cycling the key faster.

 

ya its just not working properly need to dig in to the electrical a little if i want to figure it out. it doesnt come on after start until i use brakes by the way