1998 Ford Explorer GEM/Instrument Cluster Fuse Blown | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

1998 Ford Explorer GEM/Instrument Cluster Fuse Blown

Joined
March 4, 2022
Messages
13
Reaction score
3
City, State
Miami, FL
Year, Model & Trim Level
1998 Ford Explorer Sport
While driving I smelled strong electrical overheating. Then I noticed a puff of white smoke come from my fuse box area and at the same time my speedometer stopped working, I watched the needle go down to zero. None of the rest of the instruments stopped working, tach, battery, oil, etc. all still operational. And when I tried to roll down my power windows to let the smoke out they didn't work. I stopped the vehicle, disconnected the battery and pulled the fuses and saw #25 was blown, its contacts blackened. Manual tells me that's for the GEM and Instrument Cluster. Trying to troubleshoot which system is most likely culprit, blown fuse from one also disables the other. Suggestions?
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





One thing I'd try, is disconnect the GEM and put a new fuse in, turn key to run position and see if fuse blows. I mean if it does, seems like the speedo is bad, but I'm not 100% sure it would blow even if it is bad, with the GEM disconnected so not having it blow, I can't assume is proof the speedo is good.

Likewise you could disconnect the speedo, and if the fuse blows with only the GEM, seems like the GEM is bad. I'd also disconnect both and use a multimeter to measure for resistance to ground in case the wiring has a short.

That's about all I have to suggest remotely posting in a topic unless you uncover more info. There are wiring diagrams linked in my sig below.
 






One thing I'd try, is disconnect the GEM and put a new fuse in, turn key to run position and see if fuse blows. I mean if it does, seems like the speedo is bad, but I'm not 100% sure it would blow even if it is bad, with the GEM disconnected so not having it blow, I can't assume is proof the speedo is good.

Likewise you could disconnect the speedo, and if the fuse blows with only the GEM, seems like the GEM is bad. I'd also disconnect both and use a multimeter to measure for resistance to ground in case the wiring has a short.

That's about all I have to suggest remotely posting in a topic unless you uncover more info. There are wiring diagrams linked in my sig below.
I pulled the GEM module. It looks fine, no charring or visible damage. It has no burnt odor to it, either. I'm hesitating to put the fuse in to see if it is the speedo, worried that if it doesn't blow but there's a short in the wiring for it that short could cause a fire that takes the entire vehicle with it. I see the wiring chart you put together in your .zip file, called instrument cluster 1 of 2. I've never pulled an entire dash out and been told it's a tough project on this vehicle even for someone with experience. Is there a way to get to the speedo and/or check the wiring to and from it without pulling the whole dash?
 






^ I don't know but vaguely recall that there are some topics about pulling the dash, maybe for changing the light bulbs and it didn't seem too hard. At the same time, I wouldn't want to manipulate old, cold plastic much during winter, but suspect it's a bit warmer in FL than here.

Here's one:

 






^ I don't know but vaguely recall that there are some topics about pulling the dash, maybe for changing the light bulbs and it didn't seem too hard. At the same time, I wouldn't want to manipulate old, cold plastic much during winter, but suspect it's a bit warmer in FL than here.

Here's one:

I put in the fuse with the GEM out. Started it and tried driving. The speedometer does not work. The rest of the instrument cluster is operational, like before, the tach, other gauges. Which tells me it is the speedometer itself that fried/has a short. Unless the GEM controls that but only that in the instrument cluster.

So it would appear I have to replace the speedometer, or find the wires going to or from it that shorted out. I downloaded your wiring schematic, but to be honest, I can't make heads or tails of it. Thank you for your suggestions so far, but do you have any more on that repair or links to information resources I can use?
 






I put in the fuse with the GEM out. Started it and tried driving. The speedometer does not work. The rest of the instrument cluster is operational, like before, the tach, other gauges. Which tells me it is the speedometer itself that fried/has a short. Unless the GEM controls that but only that in the instrument cluster.

So it would appear I have to replace the speedometer, or find the wires going to or from it that shorted out. I downloaded your wiring schematic, but to be honest, I can't make heads or tails of it. Thank you for your suggestions so far, but do you have any more on that repair or links to information resources I can use?
A friend suggests that the GEM might actually control the speedometer, too. Reasoning that if it has to be programmed with the vehicle specs, 2/4wheel drive, etc. that it ties into the speedometer. Is it possible to determine if the GEM is also in control of the speedo?
 






The GEM does control the speedometer. I did some web searches for this issue and found people who blew the fuse and smelled burning, but nobody posted the fix, topics just died. One thing I'd do is the sniff test, smell the gem to see if it smells burnt.

Otherwise, I can't attach the entire workshop manual but have extracted some pages from it. If the forum code still won't allow me to post it (I'll try that now), then you could message me your email address and I can email it.

Okay it looks like the attachment worked. 6.75MB PDF. That's all I've found so far. This is taken from the Workshop Manual linked in post #1 of the following topic, pages 3699 thru 38xx-something. That manual is a jumbled up mess but some keyword searches work.

 

Attachments

  • Speedometer 1996-2001 ford explorer workshop manual.pdf
    6.8 MB · Views: 133






The GEM does control the speedometer. I did some web searches for this issue and found people who blew the fuse and smelled burning, but nobody posted the fix, topics just died. One thing I'd do is the sniff test, smell the gem to see if it smells burnt.

Otherwise, I can't attach the entire workshop manual but have extracted some pages from it. If the forum code still won't allow me to post it (I'll try that now), then you could message me your email address and I can email it.

Okay it looks like the attachment worked. 6.75MB PDF. That's all I've found so far. This is taken from the Workshop Manual linked in post #1 of the following topic, pages 3699 thru 38xx-something. That manual is a jumbled up mess but some keyword searches work.

JC, thank you for all of your help so far. But I had done the sniff test and detected nothing. I even took the green board out of its black plastic casing and saw no brown or burn marks to indicate overheating failure.

The metal fuse contacts themselves have been the only evidence of overheating. And the fact that the puff of white smoke originated from just an inch or two away from the fuse box makes me wonder if what I saw and smelled came from the fuse burning out. Is that even possible, a blown fuse resulting in a strong electrical smell and a puff of white smoke?
 






Yes if you have a good nose you can smell a fuse burning when this open plastic type rather than enclosed glass or ceramic. Note sure about puff of white smoke, though a little plastic might have vaporized. Heh, you could light the blown fuse on fire and see if it makes a similar scent to what you smelled.

Even so, we're back to wondering what the cause was. The workshop manual pages and a multimeter may be enough to check for some potential shorts.
 






So here is what I got for you:

Fuse #25, 7.5 amps - 12 volts to GEM, PATS anti theft module and the speedometer. Wire for all of these is W/Y = white with yellow stripe. All these are hot at all times.

The speedometer circuit consists of the 12v feed fuse #25. The vehicle speed signal comes from the rear ABS sensor located on the front of the rear axle.

The ABS needs that same signal for operation. If it wasn't working you would have other problems.
If you have 12 volts on the W/Y wire to the speedo. I would agree with you on it being the speedometer.

GEM's are specific to the vehicle either 4 wheel or 2 wheel drive. My 98 Sport gem, has "sport utility 4x2". On the label.

Based on my research the GEM does not control the speedo. Just shares the same 12 volt feed of fuse #25.

I have a 98 Sport 2 wheel drive. I used the 98 Ford Explorer manuals for reference here.

speedo.jpg speedo 2.jpg
 






Based on my research the GEM does not control the speedo. Just shares the same 12 volt feed of fuse #25.

I think you're right, just double checked and the speed sensor goes through the ABS module, that's where it's translated.
 






While driving I smelled strong electrical overheating. Then I noticed a puff of white smoke come from my fuse box area and at the same time my speedometer stopped working, I watched the needle go down to zero. None of the rest of the instruments stopped working, tach, battery, oil, etc. all still operational. And when I tried to roll down my power windows to let the smoke out they didn't work. I stopped the vehicle, disconnected the battery and pulled the fuses and saw #25 was blown, its contacts blackened. Manual tells me that's for the GEM and Instrument Cluster. Trying to troubleshoot which system is most likely culprit, blown fuse from one also disables the other. Suggestions?
I drive a 95 ford explorer XLT. and the same thing happened to me. While driving, I smelled a strong burning electronics smell and some smoke came from my instrument cluster. So I did what any normal person would. I pulled over thinking my vehicle was gonna burst into flames. Got it towed to a shop to see if it was anything super major and found out it blew a couple of my fuses and once all were replaced, I didn't have any problem. However, my speedometer doesn't work so I have to use an app on my phone. Is there something seriously wrong with my vehicle or was it just speedometer giving up the ghost that caused it blow a few fuses?
 






^ Probably just the speedometer (or wiring to it), but do check all things powered by the fuses that blew... it is odd that two blew rather than only one.
 






The GEM modules are lately becoming an issue, being 20+ years old, the electronics are starting to fail. That's common for many car electronics devices after so long. Repair shops handle radios a lot, as well as the EATC or compass, trip computers etc.

The GEM came in four versions from 1995-2001. The 95-97's are alike except for the 4WD option, and the same for 1998-2001. So you can hunt another GEM by those two model groups, plus the choice of 2WD(also AWD), and 4WD. The GEM's should be labeled as 4x2 or 4x4 somewhere on them.
 






Back
Top