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Electrical Help please asap

DanCain

Member
Joined
May 29, 2013
Messages
11
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City, State
Oregon
Year, Model & Trim Level
98 explorer
Hello all and thanks. What I have here is a 98 Explorer awd 4.0 Sohc. The truck was parked for 8 months in Oregon weather due to trans losing reverse which I have just fixed by replacing transmission. Now for other issues... here is a list of what currently does not work(or stop working) in the electronics.

1. Wipers stay on high speed constantly. no stopping them while key is on without unplugging wiper motor.

2. No power windows

3. No 4x4 selection seems to work as 4x4 light in cluster does not come on and acceleration feels the same with 4low selected as if in the "auto" selection.

4. Overhead display is blank, no led lights at all

5. blinkers do not work, hazards do work although I believe they are in a different circuit in most vehicles.

I have tested all of these with wiper motor plugged in and unplugged thinking I may break a circuit unplugging it but all remains the same.

I have removed the MFS from column and wipers maintained high speed function with the MFS removed.

I have read a bit about the GEM inside of this vehicle and it does seem to be able to effect some of these functions but not all of them.

I am at a loss and this is their only vehicle. No blinkers=ticket Windows stuck up = no arm siginals to prevent ticket. Having to pull over in this Oregon choppy rain to have no wipers or high speed wipers does not sound safe. :thumbdwn:

I greatly appreciate any input on this situation. Thank you in advance. :)
 



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This stuff all worked before parking it? Just shooting from the hip, it all sounds unrelated.

As for the 4x4, did you plug the harness back into the transfer case after replacing the trans?

The wipers and turn signals may have a common beast involved as they are all on the same "switch". Windows and overhead "may" be on the same fuse (i'd check that fuse for sure).

Let me look around and see if I can turn up a decent body wiring diagram for the vehicle. They arent easy to find.
 






The radio did not work before parking it. Everything else did. I have triple checked the xfer case motor plug and it is in proper shape, plugged and mounted. I have checked all fuses in both boxes. Have not done a relay test on the relays in main junction box. No blown fuses. As for the wipers Ive been told on this specific truck if the MFS is bad and you unplug it the wipers should stop. Unplugged both plugs and wipers sill going high speed.
 






I can't find any wiring diagrams with a google image search. Hopefully someone else may come up with one. There's not a lot I can say without seeing the Wiring Diagram.

Do you know what MFS stands for? The acronym isn't one I've head before.

It's odd because the wipers are clearly getting power when they shouldn't and everything else isn't getting power when it should. If you have a voltmeter you should see that the fuse box is actually getting power to the 4x4 fuse as well as the window fuse. If not, it could be a bad fusable link or relay.

Any other takers on this?

Let me look again and maybe find a specific diagram for the wiper and turn signal circuit.
 












From the looks of it, the switch on the turn signal lever sends a signal to the Central Timer Module or GEM which activates relays to engage the wipers. This particular diagram doesnt involve the switch. I'm leaning towards the CTM/GEM being the problem. There is a relay in there that selects between hi and low operation and another relay to supply power. The hi/low relay must be energized to make them run in hi, it functions in low when relay is "off". The other relay also must be energized to make the wipers run at all. I see no way this could happen aside from a malfunction in the CTM/GEM.

However, this is the diagram for the turn signals/hazards.

http://ww2.justanswer.com/uploads/s420/2010-11-12_203412_98_explorer_turn_signal_wiring_diagram.jpg

It's showing that both are controlled through a multifunction switch (MFS Ha!) It strikes me as odd you would lose turn signal but not Hazards. Unless of course the multifuntion switch is the problem. Which it could be, it's possible the wipers are controlled through this switch also. Though it seems quite odd the wipers would keep running with the switch disconnected.

I'm getting the distinct impression that something very bad happened to the electrical system on this truck. Like maybe someone tried to jump start it with the cables backwards.
 






Hi thanks again for looking up info on this and taking your brain to help me try and figure this out. I am 80% sure its the GEM acting up. I have also read they can be hit by water in some situations... I have placed blame on others for hooking up cables backwards on this rig. I was not there to witness it but the owners have jumped it a few times. It was my first remark toward the issues before I was asked to take a look at it.

Is there two GEM/CTM in the vehicle? the diagram shows two. I know location of 1 which is the GEM behind radio. there is another computer of sorts inside the engine bay on firewall although not to sure what it does and i figured it was part of the running gear control which if so it could be causing the 4x4 issues I am having.

The MFS has two different plugs on it. one Is for the turn/headlight/squirt and other is for hazards I am thinking... not sure though :)

I still do not understand how the GEM can effect all of these issues at once though and the GEM seems to not pertain to the blinkers at all. Could it simply be the wiper motor has shorted out windings causing blinkers and wiper to go haywire? The windows could have broke wires inside door jab causing windows not to work? still does not sort out the blacked out overhead or radio or 4x4...

I am boggled :confused:
 






So looking further at diagram I see the GEM is in same circuit as blinkers/hazard if I am correct. So GEM could effect that if that is the case.

About the 4x4 I am starting to wonder if possibly the bulb in the 4x4 indicator has gone out inside of cluster. I did not run in 4x4lo or hi for much distance at all. Although I do have experience in how a 4x4 feels when it is engaged and this sure did not feel like it for the little romp of gas I gave it with 4x4lo selected. Felt like 2x4. Is it possible the GEM controls the 4x4 also?
 






The computer on the firewall is the PCM. That's your engine/emissions computer. It *may* control the 4x4 too but I'm pretty sure that one is linked in with the ABS computer (located near the master cylinder and possibly part of the ABS pump).

I'm not certain there is more than one CTM/GEM. The diagram may just be drawn that way for (lack of)clarity.

To be perfectly honest with you, you're gonna be pulling your hair out for a long time with this. Probably replacing parts and wishing. Unless you can get the complete electrical system diagram for this truck. These problems are not all related which is what makes me about 99% sure this thing was jump started incorrectly. You could be looking at blown fusable links causing some of the problems and a shorted out GEM causing the others. It's SOOOOO difficult to say.

The best place I know of to get complete electrical diagrams is from Mitchell. They have discs at Autozone you can buy. It's a generic disc of Mitchell software and lets you link up to their network and download and view what you need. The disc has a one year subscription for ONE vehicle for one year. I'm not sure what it costs, but it's less than $30. Not only electrical, but it includes anything and everything you need as far as tech bulletins, step by step instructions for repairs and all the rest. It's what the pro's use.

Is this your truck or are you working out of a shop or is this a side job/favor? If it's not yours and you're not making some good money on the repairs I'd tell the owner to take it and get it gone. This is going to be a headache.
 






I'm not seeing that the turn signal and hazards are wired in with the CTM/GEM. They are wired into the multi function switch. I can only assume the wipers go through the multi function switch too. However the multi function switch goes into the CTM/GEM before going to thw wiper relays. The turn signals appear to go straight to the lamps from the MFS. Though the hazards working and the turn signals not working makes it seem the MFS has malfunctioned too.
 






The MFS was a little toasty looking on inside also as if it had got hot at one point.

Its a 76 yr old friends truck that actually belongs to his wife's daughter. None of which have the proper money to get it done at a shop. I have done work on many cars so for them cheap labor and for me getting to help others + always a learning experience :)
I have more paitence than most when it comes to technical issues so the CD you suggested sounds like something I may be studying soon. All up to him and what he wants done with it but just replaced trans in it $1k total and now all these other issues... :( The drivers have 2 kids and it is there only truck so I want it to be the best I can for the kids.
 






I am thinking I may go to junkyard and get a different MFS, GEM, and some relays... then do the swap and check method. Ive read if you swap the GEM you have to get it reprogrammed by Ford? Even if out of same vehicle/model/year?
 






Hello all and thanks. What I have here is a 98 Explorer awd 4.0 Sohc. The truck was parked for 8 months in Oregon weather due to trans losing reverse which I have just fixed by replacing transmission. Now for other issues... here is a list of what currently does not work(or stop working) in the electronics.

1. Wipers stay on high speed constantly. no stopping them while key is on without unplugging wiper motor.

2. No power windows

3. No 4x4 selection seems to work as 4x4 light in cluster does not come on and acceleration feels the same with 4low selected as if in the "auto" selection.

4. Overhead display is blank, no
led lights at all

5. blinkers do not work, hazards do work although I believe they are in a different circuit in most vehicles.

I have tested all of these with wiper motor plugged in and unplugged thinking I may break a circuit unplugging it but all remains the same.

I have removed the MFS from column and wipers maintained high speed function with the MFS removed.

I have read a bit about the GEM inside of this vehicle and it does seem to be able to effect some of these functions but not all of them.

I am at a loss and this is their only vehicle. No blinkers=ticket Windows stuck up = no arm siginals to prevent ticket. Having to pull over in this Oregon choppy rain to have no wipers or high speed wipers does not sound safe. :thumbdwn:

I greatly appreciate any input on this situation. Thank you in advance. :)
Lots of issues man. Best way is to hire a good mechanic and save some time. I will surely some money as I am not all good at repairing:salute::salute:
 






Gem from same exact truck will work its behind the radio to the left black box about the size of an old VHS. It all points to the gem but I would look hard at the harness around it make sure mice didn't chew it up while it sat.
 






Gem from same exact truck will work its behind the radio to the left black box about the size of an old VHS. It all points to the gem but I would look hard at the harness around it make sure mice didn't chew it up while it sat.

That is great news. I plan on pulling his GEM and checking wires/grounds and plugs for corrosion. If I see nothing wrong then I will go get one out of exact vehicle and give it a try. Thanks to all who have helped me and I will defiantly post an update once I get this figured out. :salute:
 






It definitely couldn't hurt to replace the GEM for starters. I'm pretty sure the MFS is gonna need it too, I REALLY dont think the turns signals go through the GEM. I'm pretty sure the windows do not either, but that's a simpler circuit.

Once the GEM and MFS are replaced you're gonna wanna check for voltage present at the fuse box for any circuits that aren't working. There are fusable links between battery positive and the underhood junction. A backwards jumpstart is a sure way to blow them. You'll know they are blown if there's no voltage at the junction box.
 






And on the by and by, I think it's cool to do some charity work now and again too. Some good karma is worth a lot more than money sometimes.
 






Great online source for wiring diagrams:
Auto - Online Repair Info
http://search.ebscohost.com/
Login ID: rrcc
Login PW: rebsco
Select: Auto Repair Reference Center
Fill in: Find Your Vehicle
Follow prompts down to Wiring Diagrams.

I use this all the time. Good luck.
 






Great online source for wiring diagrams:
Auto - Online Repair Info
http://search.ebscohost.com/
Login ID: rrcc
Login PW: rebsco
Select: Auto Repair Reference Center
Fill in: Find Your Vehicle
Follow prompts down to Wiring Diagrams.

I use this all the time. Good luck.

I found a different post where you had listed this and I previously bookmarked it. =) MANY MANY thanks for this website and u/p for it. :thumbsup::thumbsup:


On another note I am going to yards today to get a diffrent GEM and see what happens =) MFS also I presume.
 



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And on the inline fuse idea.. My dad suggested this to me but I would think the wipers would not work if one was blown. They get power just do not do anything other than run on high. :thumbdwn:

If GEM/MFS do not help issues, I will however start using the VOM on fuse panel as suggested and go from there. :)

OH and the radio not working...... pulled it out to get the GEM out and realized it is not even the proper radio and not plugged in. This truck has 1 wide plug and one square one for the radio. radio only accepts two or three square plugs. :eek: Gotta love the used car stores. :scratch:
 






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