Which Wires are for the fuel gauge on my 94 Explorer going thru the firewall? Gauge Reads Empty

[VA7LFD]

I have a 94LE X which is currently running perfectly but fuel gauge is not working. Has been reading empty since I owned the truck. I want to verify the resistance reading before dropping the tank just in case it's the anti-slosh module on the dash and not the float that's the issue. Is there a wiring diagram I can find on this forum or somewhere so I can check the resistance on the fuel gauge wires at various levels of fuel? I did try taking the dash out but the speedo cable didn't have any slack. I guess I will have to release from the transmission for more slack.. Is it easy to get at the wires at the firewall? I attached a photo here. All I need is to poke at the wires with a multimeter safely? Thanks for any info....

 

[~X~]

I've been through this a few times & it has been the slosh module most of the time. Last time I went right to the module & covered the group of 3 pins with tape then soldered a jumper on the back of the 2 pin section.

You can see the slosh on the gauge but it's not that bad.......alot better than no gauge. You do need to disconnect the cable from the trans to get slack in the speedo cable to pull the cluster.

Search results for query: Slosh module

www.explorerforum.com

 

[JustinGibson]

I have a 94LE X which is currently running perfectly but fuel gauge is not working. Has been reading empty since I owned the truck. I want to verify the resistance reading before dropping the tank just in case it's the anti-slosh module on the dash and not the float that's the issue. Is there a wiring diagram I can find on this forum or somewhere so I can check the resistance on the fuel gauge wires at various levels of fuel? I did try taking the dash out but the speedo cable didn't have any slack. I guess I will have to release from the transmission for more slack.. Is it easy to get at the wires at the firewall? I attached a photo here. All I need is to poke at the wires with a multimeter safely? Thanks for any info....

View attachment 330394

If it isn't the slosh module rockauto has the Delphi premium fuel pump assembly for only $75. Fixed my empty fuel gauge (bad float) and gave me peace of mind not driving around with 180,000 miles and 27 years on it.

 

[VA7LFD]

If it isn't the slosh module rockauto has the Delphi premium fuel pump assembly for only $75. Fixed my empty fuel gauge (bad float) and gave me peace of mind not driving around with 180,000 miles and 27 years on i

If it isn't the slosh module rockauto has the Delphi premium fuel pump assembly for only $75. Fixed my empty fuel gauge (bad float) and gave me peace of mind not driving around with 180,000 miles and 27 years on it.

Thanks will verify it isnt slosh module first. Living in Kanada Rockauto is a saviour! Close to 300 bucks at our auto stores up here. Ive learned to order from Rockauto

 

[JSWarrell]

From my EVTM:

Actually, I believe you can test the sending unit without dropping the tank. The harness is located on the driver side just above the rear axle. Mine was hanging down, but I think it's usually clipped inside the frame rail.

Unplug that and connect test leads to these two pins, circled in red, and measure resistance:

As stated by the wiring diagram, the sending unit will read 145 ohms full and 22.4 ohms empty. I just happened to have topped off my tank not too long ago, so my reading was quite accurate. If you're within this range, your sending unit is good.

Unfortunately, the anti-slosh module does require removal of the instrument cluster to test it, and really the pinpoint tests in my factory service manual aren't very DIY friendly. I think the easiest way to see if that's bad is to bypass the module completely with a jumper, after verifying your sending unit is good, of course.

Those are the two major failure points in the system. The only other easy check you can make since you got that far is in the harness itself, which you can do by unplugging the connector "B" (not the gray one, according to the EVTM) from the instrument cluster and doing a resistance check from pin 5 (yellow/white wire) to ground. You should get roughly the same reading as the sending unit itself, maybe with a tiny amount extra from the harness itself.

 

[VA7LFD]

Thank you for the informative photos and diagram. Will attempt this next few days. Will get back to you with results

 

[VA7LFD]

Just confirmed! Yay! It's the float in the tank. It reads 16.8 ohms with less than a quarter tank and 17 ohms completely full. Now do I drop the tank or try to get at it from the top by pulling the carpet back and cut a very nice and cautious not to deep access through the metal. I believe someone actually did the proper measurements and stenciled what needed to be cut to get at the float assembly here on this forum. I will look. But thanks for the info. Might have to wait a while to do it or maybe not. Depends......

 

[JSWarrell]

Personally I never liked the idea of cutting an access hole for the fuel pump, but that's just my opinion. It's pretty easy to locate. You can cut a square hole underneath the rear seat where the metal sits flat after it raises up from the floor. There's a couple videos on youtube that show it, but the pump sits a bit farther back and can be a little tough to maneuver out of there.

Dropping the tank gives you more room to work, it's just a bit more time consuming, and you're better off waiting until your tank is almost empty.
I kind of glossed over the process of dropping the tank in my EVAP line repair thread, the only tricky part for me was getting the filler neck back on all the way, and the bolt that runs through the frame wasn't that easy for me to get a socket on either. It'd be a lot better if I could've taken the wheel off, but I had it on ramps. I also didn't show disconnecting the fuel lines because I didn't have to for that job, but I think they use the same size tool as the fuel filter.