bpearson

Just got a (new to me) 1996 XJ with manual trans. My 6th Jeep and 3rd XJ, had a '92 and '98, and still have 2000 Wrangler so I'm pretty familiar with them. Everything works well, it runs great, only problem both the Temp and Fuel gauges are dead, read zero and never move. I know the 1996 was the transitional (aka bastard) year from gen2 to gen3 cherokees, so some things are more like a '97. The engine appears to have only one temp sensor, at the thermostat housing. I do not see a sensor at the rear of the engine near the firewall...although I do see a wire that's not plugged-in, that looks like it might could go to that sensor if it existed. It's a single wire, the connector is sorta waterproof-looking and it would appear the connection itself is slightly blade-shaped. If I ground that wire with the key on, the gauge on the dash doesn't move.

Have not dug into the fuel gauge yet. Also noticed a couple of fuses appear to be missing in the fusebox, not sure if that's related but am gonna replace them and see what happens. I should preface this by saying again, it's new to me. Might be a replacement engine, although I have no reason to believe it's anything other than OEM, not sure exactly how I would tell though.

Any suggestions where to start?

PatHenry

The 96 should have the temp sensor at the back of the head. That single wire is the original connector.

It could be a replacement head out of a newer 4.0. You might want to see if you can test the gauge at the instrument cluster and then probably it will be a big PITA of following wiring to see what goes where and how it has been modified from the original.

Does your T-stat housing have a 2nd sensor in it?

bpearson

I was thinking the same thing, that's where the gauge sensor should plug into, at that single loose wire...but when I ground that wire, nothing happens to the gauge, just sits at zero. I would expect it to max out if indeed it was the temp gauge wire...unless the sensor is missing AND the gauge is bad, which would be alot of coincidence. Yes I understand if the head was from a 97 or later, it would not have the threaded hole for a sensor. My plan was to add a sensor somewhere, like in-line the radiator hose etc, and connect that loose single wire. But now I'm thinking that won't work, because grounding that wire has no effect on the temp gauge.

Maybe being a 1996 , could it have 1997 gauges/sensors (single sensor at the thermostat housing, ECM controls the temp gauge) but perhaps the wiring harness still had the wire & connector for a separate gauge sensor, and it just wasn't used or needed.

PatHenry

I doubt they used the old wiring and also correctly wired up the 97+ sensor (from the factory).
I would bet that the head or engine was replaced and now the only question is what the PO did regarding the sensors/wiring. Likely they just left it and ignored the lack of a functional gauge, but it's hard to say without digging into it.

Did you check/clean the connector when you
jumped it to ground? In other words - is it possible the connector is corroded or separated internally such that you didn't get a good connection to ground? That connector has been exposed to the elements for who-knows-how-long.

First off - let's confirm it's the temp gauge - I've inserted a pic from my 95 - is that the connector?

If yes, considering you're planning on relocating it anyway, I'd cut the connector off and strip the wires and retry jumping the wire itself and see if that affects the gauge.

Then go from there...

bpearson

sorry I forgot to answer your question, yes it does have the sensor on the thermostat housing. It has two wires going to it. I assume this sends info to the ECM, because when I unplugged it with the engine running and plugged it back in, I got a check engine light (cleared by removing battery cable). So that sensor is no doubt connected to the ECM. I just don't know if the ECM is then connected to the temp gauge or not

bpearson

Thanks for the picture! Yes that looks just like the connector on the single dangling wire. I just don't have that sensor to plug into!

Thanks for that suggestion, yes perhaps it's corroded and I just didn't get a good connection when trying to ground that connector....I stuck a paper clip down in it. I can try stripping back the wire and see if that works, good idea. I'll try that again after work and see if I can get any movement out of the gauge...will update!

PatHenry

Yeah, the sensor on the t-stat housing is the engine control sensor. In a 96 and earlier it just sends temp info to the computer. Your aux fan should kick on if you disconnect it while the engine is running.

I'd relocate the Temp Sending unit (the gauge sensor) into the t-stat housing. There are a bunch of videos and instructions online for doing this - also the t-stat housing is easily replaceable and surprisingly inexpensive (in case you screw it up when drilling/tapping). Obviously the first thing is to get the wiring squared away.

PatHenry

When I replaced the Temp sending unit (you can see it's nice and shiny), the old Temp switch (I had the idiot light instrument cluster originally and swapped in the full gauge cluster) literally crumbed apart in my hands. I had to pick pieces of it out of the connector before installing the new Sending unit. However, my temp gauge works beautifully now.

Also use an actual wire when testing - paper clips may or may not be good conductors depending on what they're made of.

bpearson

Will do thanks, I'll post back how it turns out after I give it a try. I'll use a copper wire this time to test it with the connector on, and then if it still doesn't make the gauge move I may cut the connector off (leaving a little wire so I could solder to it) and try grounding the wire directly. Yeah I noticed the thermostat housings are really cheap...the wheels are already turning about how to install another sensor there, I've seen pics and videos as well. Seems simple enough...and probably will be the answer if I can't get the OEM gage working, I may just install an aftermarket. I just hate to hang something off the dash when it's got such a nice stock interior. Love to get the original working!

PatHenry

The instrument cluster comes out very easily. If your actual gauge is bad you can probably find a replacement cluster or even swap out the actual gauge (I've heard of this but have never considered doing it myself.).

djgrayxj

Note from DJ
If my notes are correct you’re inside fuse panel is still above you left foot. If this is correct I think it might be good idea if you have a very good exam of Fuse #17 which is rated at 7.5 Amps.

The reason is it is protecting the following items; the INSTRUMENT CLUSTER GAUGES, headlamp delay module, chime module, overhead console.

If this fuse is bad or missing or not making good contact the listed items will not work properly.

Don’t get zoned in on the fact that that you have a possible connector for gage temperature sensor but no sensor. Your Jeep maybe have been early production 96 with some leftover 95 wiring harness.

Your temperature gage has a good possibility that is governed by the two wire sensor you already have just like the 97 plus Jeeps.

Keep us poste with your progress or more questions.

Fixmy59bug

Hmmm. I'll be following this thread with great interest...

I have a 94 XJ with the 4.0 and am having the same exactly problem. I even installed a new sensor.

I pulled the wire out of the grey terminal housing and held it directly to the bolt on the firewall for the ground strap. So it was bare terminal directly to ground and my gauge never moved either.

BPearson, If you pull the black clip off the bottom of the connector housing, the wire will pull out. That way you dont have to cut & solder.

Fixmy59bug

DJ Gray, Could fuse #17 still be a possibility if all other gauges work (tach, speedo, temp, oil pressure, and fuel all work fine.)?

djgrayxj

Note from DJ to 59Bug
I think not.

Martlor13

Still wondering about this haha