Testing the 4x4 computer in the rear.

[Wakeboy1337]

I have the computer out of the truck, out of the case and in my lap. Is there any kinds of test I can run on it with a multimeter or with it in the truck to see if it is bad? I press the 4x4 button on the dash and I have no clicks at all, no lights as well. So if this checks out as good then I can know if it's the buttons or not. Or if one of the relays is bad can I take these off and solder new ones on the board?

Thanks guys.

 

[Wakeboy1337]

Nobody? Really?

 

[hoss_hanna]

i haven't had to mess with my 4x4 comp yet so im not sure but i think it has 2 led's on it for testing? with it plugged in they should light up when the switch is hit i think. what made u go with pulling the 4x4 comp? wouldn't it have been easier to test the switch?

 

[BWTGUY]

The quickest, easiest way to check the system is to get a replacement switch set (4 x4 Hi and 4 X 4 Lo) from a junk yard (bearing in mind it could be bad also) and try the new switch set to see if the problem disappears. I actually used two sets from a pair of 1992s at the local Pick-Ur-Parts so had three chances for a bad switch<grin>. My 4 X 4 controller (or the Electronic Control Module, ECM as FORD refers to it) tested good in the Ex but when I replaced it with one I had pulled from a scrapped 92, my no shift to Lo 4 X 4 went away and all worked as it was designed. I now have two spare sets of 4 X 4 switches and a very bad ECM as both electrolytic capacitors on the motherboard are leaking so I suspect that was the problem. Ex years are sort of like dog years being equal to 5-6 human years.