hi, i have a 90 f150 w/duel tanks the problem is that my fuel pumps are not working when i turn the key ON, also the gas gauge is no longer accurate i put a test light on the fuel pump selector switch and it gave me a very DIM light, i then put the light on my power door lock switch (just to make sure the test light was working) and it lit up very bright. i then unplugged the fuel selector switch and put the light on the connector itself and nothing no light. i grounded the #6 on the EEC connector and the fuel pump relay is working. would a bad fuel selector switch cause the fuel pumps to stop working? along with the gas gauge? and also i need to know what color is the power wire on both tanks so i can see if there is power back there thanks Darrin

 

IM not sure but on the 90 is there a separte fuse in the block that takes care of the fuel pumps because i think my 95 does but yea if the switch is bad too it will cause problems, usually the truck will only crank and wont start

 

Hi Mechanical Mike 08, so if the switch goes bad, I have a crank no start, can it go bad just sitting? I have a weird front tank prime sound, and the rear will no longer prime, is there a way to test the switch?

 

Watch the dates. You are responding to a 13 year old thread and he hasn't logged in for 8 years.
Your best bet is to check fuel pressure and that will tell you if fuel is reaching the fuel rail. A bad pump is more likely than that switch going bad.

 

Ahh I missed that thanks! I will get a gauge on it then! take it from there! thanks and happy holidays!

 

when parked gauges worked right, also now, both tanks show overfull. like pegged.