Hey all.
Been lurking here awhile and you've helped tons! Have needed your info a few times since buying my 91 4.9L Lariat.

Here is the current problem: I have a bad connection in the wiring that leaves my fuel tank selector switch. Sometimes the midship fuel pump does not receive power and will not prime when I turn the key on.

I know where the problem is, as I am missing the nut that holds the windshield wiper switch in place on the dash, have had no luck finding a replacement and so the switch rests on the fuel wiring.

Of course this means that every so often I hit a bump and my fuel pump power cuts out, check engine light comes on, engine bogs out and I wiggle the wiper switch and everything is fine again.

So question is: anyone know which wire is which? My Haines manual is no help (at least to me). I can't read a schematic worth a damn, but I can splice wire, so if I just knew which wire I would be good to go.

This is by far not my truck's only issue, but it is the most pressing (its winter now so I won't worry about the overheating until May).

Thanks!

 

"The Junkyard!.................. Is your Friend!.............Sometimes it becomes your best friend,.......Sometimes.............your only friend!" Semper Fi! Seriously, go to the junkyard and get the retaining nut you need. They keep those big nastyass dogs locked up till after they close! But try not to be the last one out.

 

Fix it right but if you can't, red/yellow is power in. Red to the front tank, brown/white to the rear. You will have to splice others to make the gas gauge bypass the switch too, but I don't have colors for those.