87 Silverado dual tank issue

[biggsteve97]

I have an 87 Silverado and recently I have noticed and issue when trying to switch from the right tank to the left tank. When I flip the switch, nothing happens. The right pump continues to run and the guage still continues to read the right tank. If I rock the switch several times it might switch to the left tank. Is this the switch or a wiring issue? I have checked the connections and wiring under the truck and everything looks good. Have not had a chance to check the wiring in the dash yet to the switch. I am leaning towards the switch but I am unsure. The last time I had a problem with the switch was 14 years ago and it fell apart literrally.

[parrisc19844x4_468]

Sounds like the switch. The switch is right there on the lower dash, pull the wires and wire in a simple switch for now, it should work. If its not there , then it is back under the right tank where the selector value/switch is located. Might have to replace it.

[biggsteve97]

I will give that a shot and see what happens.

[Malo83]

It's the switch, I have the same problem with my 83, have to rock the switch several times to change tanks

[RandyP]

Seems when my switch went bad in my '87 the truck quit running all together. Had me baffled for a bit but thankfully I had an extra in my toolbox and it was one of the first things I swapped trying to make it start.

[SourTooth307]

I have the dual tank set up in my 84, but no second tank installed so I've never flipped mine to see if it works. After reading this I might consider ordering a replacement switch from LMC Truck or something just as a precaution.....

[RandyP]

An '84 model does not require power to the fuel pump inside the tank to make the truck run. I think that was what failed in my switch, was it calling for power to the in tank fuel pump to let the truck run.

[dfrank]

Mine did that and it was the fuel tank selector valve under the right frame rail.

[biggsteve97]

I pulled the switch out of the dash and found out it was the original switch. Was a bit surprised with 440,500 miles i thought i would have changed it by now. Also one of the terminals for the left tan was completely loose and about to fall off the switch as well as the little circuit board was loose in the switch. Found one at oreilly for $13 so i just put a new one in and everything is workin great again. Its weird having an all black and shiny switch on the dash now. The original switch was severely faded and chalky white.

[biggsteve97]

When my selector valve went years ago it stopped switching the return line and pumped all the full from the left tank into the right tank. At tye time the right tank had 3inches of rust in it and i couldnt use it so it took a couple of tanks before fuel started coming out of the top of the tank and the charcoal cannister up front. When that happened atleast i figured out why i only got 40-50 miles per tank until then.