fuse keeps blowing

[gdtrfb]

HI all
in my stock 71fj40, the fuse that runs the fuel gauge keeps blowing, is there a wiring diagram available on line? its really annoying not knowing how much fuel is in the tank.

Thanks

 

[dgangle]

these are fun to troubleshoot.

jumper the fuse and look for the smoking wire....just kidding

View attachment fj40_wiring_diagram.pdf

this is for a 75-later model but should be similar. The 15A "heater" fuse also powers the oil & water temp gauges as well as the heater. If this fuse is blowing the other gauges shouldn't be working either. If they are you have other problems.

 

[gdtrfb]

[QUOTE
jumper the fuse and look for the smoking wire
[/QUOTE]

thought about that!! but it is the fuel gauge wire after all!
Thanks for the diagram!

 

[65swb45]

Like dgangle said, the other guages should be going out as well. Are they?

 

[dgangle]

....Bueller?

 

[gdtrfb]

....Bueller?

ouch.. no its just the one fuse, then the fuel gauge stops working, I parked it for the winter, Slider is kind of a rolling project.. I just fired it up over the holiday and remembered the fuel gauge/fuse issue. I was just wondering if the wire just goes to the sending unit alone or elsewhere too? I have no garage and bout 3" of white stuff on the ground here.

 

[Pin_Head]

The same fuse appears to feed the back up light and transfer case indicator light. Basically the short could be anywhere in the circuit. If the gauges don't deflect to the right, it is not shorted on the sender side of the gauges. To find the short, you pull the fuse and disconnect the final ends of all the devices on the circuit (eg. the senders and light bulbs) and measure the resistance between the fuse block (not the battery side) and ground. There should be very high resistance normally. If it is low resistance start following the wire along its path to the next connection. Wiggle it where it crosses metal and see if the resistance goes back to normal. Disconnect its next connection and see if the resistance becomes normal. Keep following all the next branches until you find where the short is. It is a PITA, since a lot of the wires on this circuit are under the dash. You might want to remove the gauge cluster.

 

[dgangle]

I missed the backup-light leg of the diagram but where on the wiring diagram is the TC indictor lamp you mention?

 

[Pin_Head]

Here you go.

 

[dgangle]

OK, more year-appropriate diagram I presume?

 

[Pin_Head]

It is a '71 diagram, which is what I assumed was appropriate from his sig line.

 

[gdtrfb]

Thanks Pin Head, Thats what I needed, I'll check it out this week end.

 

[65swb45]

The same fuse appears to feed the back up light and transfer case indicator light. Basically the short could be anywhere in the circuit. If the gauges don't deflect to the right, it is not shorted on the sender side of the gauges. To find the short, you pull the fuse and disconnect the final ends of all the devices on the circuit (eg. the senders and light bulbs) and measure the resistance between the fuse block (not the battery side) and ground. There should be very high resistance normally. If it is low resistance start following the wire along its path to the next connection. Wiggle it where it crosses metal and see if the resistance goes back to normal. Disconnect its next connection and see if the resistance becomes normal. Keep following all the next branches until you find where the short is. It is a PITA, since a lot of the wires on this circuit are under the dash. You might want to remove the gauge cluster.

Since a lot of the '71s have been converted to floorshift without dealing with rewiring the backup light switch, I have seen many cruisers come into the shop with the backup light wiring dangling by the steering column. That would be a good place to look first.

Best

Mark A.

 

[gdtrfb]

Since a lot of the '71s have been converted to floorshift without dealing with rewiring the backup light switch, I have seen many cruisers come into the shop with the backup light wiring dangling by the steering column. That would be a good place to look first.

Best

Mark A.

will do Mark. Read the soap box last night...right on!
Wolf