Solved 1993 Ford Explorer XLT Temperature Gauge Dead

[Kamel]

Maniak, thanks for your response. Unfortunately, it came too late as I did the job today. Fortunately, it DID fix the problem! Guess I lucked out on that one.

Here are just a few notes for anyone doing this job.

NOTE: For anyone replacing this unit especially on as old of vehicle as this, plastic/rubber boot around the sending unit has hardened over the years and will not get larger. The sender I got was a generic part and the probe was much larger than the one it was replacing. Due to this, I had to hammer a screwdriver into the boot, breaking some of the boot. I highly recommend you get a part with a small probe on the top, like the OEM version and not a larger one.

I got the part in question from O'Reilly similar to the one shown here (came with a nut on the top) http://www.oreillyauto.com/site/c/detail/BWD0/WT909.oap?ck=Search_N2346_-1_-1&pt=N2346&ppt=C0331 . I was able to confirm the new part did indeed have a much larger top as the unnecessary nut that came on top of the sender easily slide right down the part I took out.

I did get a second sender from Napa which I compared to the part I took out and it looked identical in diameter (but different in other ways). I would imagine it would have kept me from needing to hammer a screwdriver into the boot breaking it, but I already had the new one in and it was a major pain to get in (also from a financial perspective if I didn't use the napa part I could return it, whereas there was no hope for the one already installed and marred up).

The sender is located on the right side of the alternator, next to the base. It is under the tubing for the A/C, the thermostat, and the 2 little wiring harnesses there to the left of where the red arrow pointed in jasonexplorer's last picture.

I took the air tube and the shield over the throttle off to improve room, but ultimately it didn't do much -- this is one of those jobs that are a tight fit and require patience and a small hand. No coolant came out for me when I did it, but there was fluid right up to the hole, could have easily stuck my finger in and gotten coolant on it.

It has an "L" shaped boot over the top with a single (green, if I recall correctly) wire coming from it. You can easily pull this right off (doesn't have threads) to get a socket over it. The stock one takes a 17mm socket but I think the replacement part I got would have had a better fitting english-system counter part, as I saw that the corners looked marred once installed. I used a deep socket, but it was the only one of the size I had so not sure if it was required.

Hope this helps anyone who does this job. It was certainly more of a pain than I thought it would be, but well worth the effort. With the right replacement part, I think it would have been much easier overall.

 

[larrydd999]

Also my thanks for all who took the time and photos! I, too, had to replace the sender a few months ago and had the same problems. With my large hands it was a bit of a struggle to get that tiny sender into that small area. I ended up using the rubber hose method. One very minor suggestion... When checking this gauge - or any other - the ignition switch needs to be on so the gauges have power. Grounding most dash gauge senders will cause the associated gauge to move so it's a quick and effective test. Don't try this with senders having multiple wires, however, since one or more of the wires will likely be connected to the battery and/or the electronics module possibly resulting in damage.

 

[DR]

Temperature Gauge Reading Low

I assume the problem is the thermostat staying open but does anyone have resistance readings for the sensor. Engine cold with air temperature around 60 degrees I get a reading of around 400 ohms. What checking I have done lets me know with heat the resistance will decrease. The temperature gauge comes up to the cold line and stalls there while driving. Around 2007 I installed a fail safe thermostat with no problems until know. Not a bad problem if you compare it to overheating. Anyone have an input on this?

 

[larrydd999]

The sender resistances are variable depending on the manufacturer, but a 400 ohm reading at 'cold' temperatures is reasonable in my experience. Hot will be somewhere around 30 ohms, again depending on the manufacturer and intended use (i.e. make, model, year, etc.). My wife's '92 ex and my '94 ex both use the same thermostat and the same sender and our gauges read quite a bit different under the same conditions.

 

[davidk]

Before you throw money at the sending unit, you should make sure the gauge and the wireing for it are working.

Its an easy test. Just take the single wire that goes to the sending unit and ground it. If the gauge and wiring is good it will peg the gauge. If it doesn't move you have other issues to fix before you change the sending unit.

~Mark

Just to make sure I understand, if the gauge and the wiring are good (grounding test: gauge is pegged with key on) then that means the sender is bad?

David

 

[Jon94]

Just to make sure I understand, if the gauge and the wiring are good (grounding test: gauge is pegged with key on) then that means the sender is bad?

David

It means the gauge and wiring are good and functioning properly, and the only other thing it could possibly be is the sender. So yes, it means the sender is bad.

 

[FR-425]

Correct.

 

[davidk]

Thanks, FR-425! That helped clarify it for me. I decided to take a gamble on the electrical connector being corroded, reamed it out a bit with a rat tail file, squirted in some Corrosion X, hooked it back up and now my temp gauge works again, at least for now.

 

[FR-425]

 

[FORDLOVER Tammy]

believe it or not guys the reason i joined this list is because i have worked on my own cars since i got my first at 14 most mechanics treat me like i have no idea my old mechanic would loan me tools . and trade me an hrs work on items his Huge hands where to Big to get into . Thanks for being here . PS i used to be a mechanic at the PDX