Did I fry my fuel level sender? (1 Viewer)

[Tofudebeest]

I unplugged everything in my driver's rear panel so I could install a set of 80 shoulder belts (which works nicely, by the way...pics later), because cutting is involved and my old panel had a hole in it for the harness to run through. When I reconnected everything, my tail lights were out, instrument cluster illumination was out and fuel level gauge was pegged high. The fuse was blown. Replaced it twice, blew in 2 seconds. Brake lights work.

Hmmm... Turns out, the fuel level sender plug was unplugged (it is hidden under the bottle jack holster thingy...which I have now removed and set aside, since my lift renders a regular bottle jack useless) and the plug to it on the harness was plugged into some other thing (why have adjacent connectors of the same size and type, man?!) that is apparently unused in my 62 (can't be a CD changer, maybe part of the rear A/C or third row seats available in other markets???). I plugged things back together, correctly this time.

Well, now my tail lights and cluster work normally, but my fuel level gauge is dead on E, and I know I have at least a half-tank. I double checked the sender plug, seated fine, even checked the plug on the sender itself (through the little floorboard access panel). Still no workie. Then, I broke down and replaced the gauge (I am a total champ at taking my instrument cluster out, disassembled, and reassembled in record time, did it so many times)...

No dice.

Sender on the tank is fried, huh? Gotta drop my tank to replace it huh? Life sucks, huh?

 

[Tofudebeest]

Tell me about after market fuel level senders and gauges.

 

[Lost]

isnt there a whole/cover under the carpet in the truck for access to the top of the tank?

when i was playing with my tank during my swap, i found the wires on top of the tank were very corroded. and the clips were near non existant

maybe you should finish painting your truck before worrying about tank levels
just kiding

 

[Tofudebeest]

You didn't read my post fully. ADHD? Remember "I double checked the sender plug, seated fine, even checked the plug on the sender itself (through the little floorboard access panel)."

Hole, not whole. And no, I'd rather drive around in a half-primered truck than run out of fuel. Right now, I roll with a 2 gallon Wesson oil jug, just in case.

 

[fliphkd778]

I'm pretty sure the sender is a variable resistor in a circuit with the gauge. As the tank level rises, the resistance would be less and more power would be sent to the mechanical gauge, causing the needle to warp more to the full side. If this is the case, then the sender does see 12V at a full tank. If what you plugged it into was greater somehow in voltage or carried more amperage than you may have cooked it.
I would check the sender's plug resistance first. If it is infinite, then the resistor has cooked and has broken the circuit. If this checks out, verify that you have 12v and ground going to the plug. The resistor could probably be replaced.

 

[NYC FJ62]

Does the FSM show a way to test the sender for continuity to verify if it's bad or not ?

Just asking because there "FSM" for VW's has a continuity test you can do to check if it's bad (on a VW).

 

[Tofudebeest]

I'll look into it...

Electrical is my weakest automotive skill, right along with mechanicals, welding, diagnostics...

Essentially, I can disassemble, reassemble, fabricate and paint...

 

[2mbb]

1. since the bottle jack lifts from the bottom of the axle, I don't understand how a lift makes it useless. It may not work with large tires, though.

2. The fuel sender mounts into the tank from the top. There is no reason to drop the tank to get to it. You go in through the access hole in the bed of the truck.

3. Here is the test procedure for the sending unit. I think it's more likely you cut or broke a wire than fried the sender.

 

[fliphkd778]

my thought exactly, the FSM diagram shows the sender as a variable resistor. Check the resistance. If you did fry it, I bet it would be possible(and cheap) to source out a new resistor.

 

[Tofudebeest]

Very cool. The bottle jack, I never felt comfortable using the axle or the plate. I always jack from the frame, or if I have jack stands ready, a floor jack on the axle or plate. I do not trust those bottle jacks. Had one slip out on me, and nearly shat myself.

Those diagrams/test procedures are not too bad looking. I am not sure the sender is removable through that hole. I did not really assess that, but it seems that the hole is merely to access the wiring.

Thanks.

What's the chance my gauge got friend and the one I put in was also bad (as opposed to the sender)? The replacement was from a cluster I bought from a parted out 62, never tested.
The original gauge was pegged high, I fixed the connectors, and then the replacement is just dead. No cut or broken wires. I am sure of it.

 

[fliphkd778]

If the original gauge was pegged then the ground below the fuel gauge symbol in the diagram had lost its connection. This will also cause the temp gauge to peg as seen they both share the same connection.

 

[Tofudebeest]

Temp gauge is long dead, replaced with an aftermarket above my stereo, along with an EGT and oil pressure.

 

[surffj62]

yes- you can pull the sender thru the hole

 

[Tofudebeest]

Not for me. Recall, I have the tank from Sheila (the HJ60). The sender is not centered like on a 2f/3FE gas tank, it is in the corner, not even visible from the access hole. I can get to the wires, but not to the sender, quite unfortunately. Sheila didn't even have that access hole.