Tank Selector Switch Blowing Fuse

[pndwind]

When I bought the truck it only ran on the rear tank, and like a dummy, I just assumed the valve was stuck. I didn't worry about it because I planned on doing tank swaps and manual valves. So during the process of going manual I thought hey! I haven't checked that fuse, and of course it was blown. Now with the fsv unplugged i'm still blowing fuses when I flip the switch. I had left the switch on the rear tank before and it read fine. My 12v wiring skills are pretty weak and I could use some help. Any suggestions?
Thanks

 

[chillman88]

When mine did that it was because the valve had stuck and burned the motor up shorting it out.

I'd unplug it and check the wires for shorts, then replace the switch if the wiring checks out.

EDIT: Sorry, apparently I can't read! The only thing that could be wrong with the FSV unplugged is a short. The FSV actually switches the gauges too, did you have a plan for switching the gauges with your manual valves?

 

[pndwind]

Spent the afternoon blowing fuses and playing with wiring. Nothing solved yet.

I was hoping to ask some questions about the following threads, join some wires and everything work like it should.
https://www.oilburners.net/threads/manual-valve-install-with-fuel-tank-switch.68315/

https://www.oilburners.net/threads/fuel-selector-valve.61231/

 

[IDIBRONCO]

I know that this isn't what you want to hear, but my advice would be to keep it on the rear tank and use a transfer pump to put fuel into the rear tank from the front one. That way, you fuel gauge will still work all of the time.

 

[Cubey]

I know that this isn't what you want to hear, but my advice would be to keep it on the rear tank and use a transfer pump to put fuel into the rear tank from the front one. That way, you fuel gauge will still work all of the time.

That's what I did on my motorhome, except it's set up to pump from rear to front since they seem to be the same size tanks. That way there is less weight further back when the rear/aux tank is empty. I have the pump on a toggle switch. An LED mounted in eyeline (not down low where I put the switch) would be a good idea so I don't forget about it being on. I will probably do that some day.

You must be registered for see images attach

 

[pndwind]

I was planning on putting black diesel in one tank.

 

[chillman88]

I was planning on putting black diesel in one tank.

This is the only reason I messed with the selector valve. It's very nice to be able to switch back to straight diesel if you run into any issues.

 

[ifrythings]

If someone swapped the fuel selector switch out and put a gasser one in, it will blow the fuse every time you switch it. To check this easy, replace the fuse, turn the key off, switch it over to the other tank, turn the key on again. If the fuse is good still you have the wrong switch, if the fuse blows you have a short in the wiring harness.

 

[pndwind]

If someone swapped the fuel selector switch out and put a gasser one in, it will blow the fuse every time you switch it. To check this easy, replace the fuse, turn the key off, switch it over to the other tank, turn the key on again. If the fuse is good still you have the wrong switch, if the fuse blows you have a short in the wiring harness.

The FSV is disconnected. Still blowing fuses.

Later in the week when I have time I guess I'll open up the wiring harness and start checking wires. Gave a visual to the loom and didn't see anything. Hard to see where it goes into the engine bay and then into cab.

Anyone have any tricks to finding the short without tracing every wire?

 

[ifrythings]

The FSV is disconnected. Still blowing fuses.

Later in the week when I have time I guess I'll open up the wiring harness and start checking wires. Gave a visual to the loom and didn't see anything. Hard to see where it goes into the engine bay and then into cab.

Anyone have any tricks to finding the short without tracing every wire?

So with the fsv disconnected, and you flipping the switch with the key OFF the fuse blows when you turn the key back on?

 

[pndwind]

So with the fsv disconnected, and you flipping the switch with the key OFF the fuse blows when you turn the key back on?

I had to go try it. It doesn't blow when doing this, but if the key is on or on accessory it blows when I switch it. It usually blows the first time but always by the third.

 

[chillman88]

I wonder if the switch is bad/dirty internally?

 

[pndwind]

I’ve replaced the switch.

 

[ifrythings]

You have the wrong switch, the gasser and diesel switches look the same but the internal contacts are different between them. Your short is the switch! Now you can either find the right switch or remember when you want to switch tanks just turn the key off first.

 

[pndwind]

I also have a gas switch. The way they are made only the correct switch will plug in. Fuses were also blowing with the old switch.