What is this?

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Aug 21, 2014
73' FJ 40 F engine...what is this part? One of the prongs on this is rusted and broke off...would this have any effect on my fuel and temp gauges not functioning?


looks like a relay of some kind.

Think you could take a picture from a bit further back? Where do the wires go?
Another pic ...this is located on the passenger side wheel next to the battery.

Horn relay.
Thanks...any way this could mess with my temp and fuel gauges? I'm trying to track down why these gauges are not working. Found this bad connection and was hoping this could be the fix.
No it shouldn't affect your gauges. Check all of your grounds.
check the fuse or fuse box the gauges all use the same power source ,as mentioned make sure they are grounded .is there a ground wire from the starter bolt to the frame ? passengers sometimes kick the wire off the fuel gauge and the temp gauge sensor gets corroded good luck
Thanks folks...I think I found the issue, looks like it may be a bad fuel gauge. It actually feeds power to the temp gauge. At least that is what I found today...I'm still trying to isolate it but this looks to be the issue...
Search "never underestimate the importance of a ground" here on mud.

Likely a ground issue.
1 wire feeds power to the gauges and they are all controlled by individual grounds .if you disconnect the fuel gauge and the rest start working look there .on some 40s the fuel gauge wire runs under the truck so any thing can happen

You got it, 7v regulator in the fuel gauge is a common problem. I made up a solid state one using a 3 pin voltage regulator.
This is a common solution you will find on the web, including this site.

for Vo = 7 volts use R1=470 ohm and R2=150 ohm.

Iq = 2.5mA
Vxx = 5V if using a 7805 regulator

or you can find a LM7807 7V regulator, but the 7805 is more available.

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