'98 Jeep Cherokee Ballast Resistor?

[Fleetmon]

I'm having issues with her Jeep and the fuel gauge....works 90% of the time but when wet (like when washing the Jeep) fuel gauge goes to empty and low fuel light is on. New pump/sending unti a few years ago to resolve but exact same problem. I noticed in the Haynes manual, the wiring is going through a ballast resistor....what and where is that? Is it built into the fuel pump relay (looks like a regular Bosch-type ice cube relay and same terminals (coils 85 &86, c, nc & no). It's not a big deal but would like to repair it if possible. Ground(s) for relay were cleaned and look good...can't duplicate wiggling wires and a spray water bottle doesn't seem to bring it on either.

Thanks in advance folks!

 

[Fleetmon]

I see in a Jeep forum some people have replaced it to resolve no fuel pump but that's not my issue....can't find it anyway.

 

[Kira]

Hello, The only thing I've ever heard of being called "ballast resistor" is the 5" long, white ceramic resistor bolted on the left (driver's) fender near the front of the car or on the firewall. It only effected the ignition system. There might be more than one. Sis didn't have trouble with her's over 71 months of Jeep ownership. Her's was a 1999 and it was on the firewall. We did sell many of them over the counter when I worked at a Dodge dealership 40 years ago.

 

[Jarlaxle]

Sounds like a bad connection...IIRC, dropping to "E" on most Chrysler vehicles means an open circuit.

 

[Fleetmon]

Thanks guys....I looked for a resistor in the engine compartment and couldn't find anything that resembled one. She's owned this since new and said the problem started about 2 years after (naturally out of warranty), when we got together, I replaced the pump/sender unit and all wiring looked good. I'll keep looking and it does sound like a bad wire/connection. It only happens when wet, like washing the Jeep....rain usually doesn't affect it and when the weather is dry, it works fine. We had an almost three month dry spell when in Houston and it worked the entire time EXCEPT the one time I washed it.

 

[Jarlaxle]

Next time it does it, maybe put an ohmmeter on the fuel gauge wiring?

 

[Smoky14]

Most instrument clusters run resistors some place in the system; that being said it usually effects all the gauges at the same time.
YMMV

 

[Fleetmon]

Thanks again guys....as an update, I removed the fuel pump relay yesterday and (actually removed all relays and fuses and removed the "cover" exposing the wiring) and cleaned connections....a few wires for various components were somewhat green and corroded and afterwards I rinsed off the Jeep, particularly in the area of the power distribution block and all is ok so far....drove it to work this morning (70+ miles and blinding rain) and gauge is reading fine. It may have been a bit of corrosion causing it all along. I'm surprised it started though as the wiring for the starter relay was in very bad shape.

 

[meep]

fuel gage and other sensors are low current. So they will use a tiny resistor. the big one on the firewall is big so that it can dissipate several amps-worth of heat. It won't be that one...

 

[Fleetmon]

I think it was one of the wires in the distribution box....been working fine today and actually washed it today (has ALWAYS killed the gauge) and it's working fine. As mentioned, I cleaned the wiring and removed a little corrosion across the contacts and all seems ok.