Well, I'm screwed. Nothing has gotten wet since the 18th, and it's run fine 'till today. On an errand run I saw a B2425 that wasn't there at the beginning of the trip. On the next restart a few minutes later, the overhead trip computer and radio were completely powerless. I drove it home OK, and started checking fuses, all of which were good. I was starting the motor intermittently as I tried to figure out what was working and what wasn't, and all of a sudden nothing happens when I turn the key. No WTS, no nothing. Fuse 30 checked fine, but putting a meter on the posts of that slot in the fuse box yields zero voltage when the key is in the ON position. No power windows, no wipers, and no fan blower - front or back, since it's an Excursion. The inside lights, cigarette lighter and both front and rear auxillary power outlets all work.

I'm thinking the either the GEM has failed catastrophically (is that even a thing?) or a ground that feeds it has done the same.

I'm supposed to load up tomorrow and leave for a trip on Wednesday, but that doesn't look good right now.

I'm open to ideas!! For starters, where are the hard-to-find grounds on these things? The ones I've checked are pristine - this is a really clean truck, if I do say so, myself - but I don't know what ones I'm missing.

Mark

 

I think you need to visit the fuse box under the dash and pull it out. I'm betting you have corrosion at the bottom at the power feed connections. I've seen it before in person and on previous threads here.

 

Thanks!! That's next. Where am I looking? I had it out before (post #3 with pics, above) and didn't see much. Are the power feed connections in those photos?

Mark

 

Have you pulled the battery cables and cleaned them - both ends, and bolted them back on?

 

Some ground locations in the engine bay. Look at the Gxxx numbers in the attachment.

 

I did, and they are clean as a whistle. I also had both batteries tested tonight, and both tested good. Fully charged, and 950-1100 CCA.

I have figured out that some fuses on the inside box are getting power, and others are not. I'll document which are and are not, but I don't understand why that would be.

Mark

 

Some circuits work with key off (hazard lamps fuse 1, cigar lighter fuse 3, glove box lamp fuse 4, horn fuse 12, stop lamps fuse 13, PCM/GEM fuse 15). Are these working?


The others need ignition key switch power, I think. Could point to the ignition switch or related wiring.
Does the ignition switch have power (underhood fuse panel, 20 and 21)?

 

Ignition switch info, if fuses 20 and 21 are hot.

Ford Ignition Slide Switch Testing (Not the Key Cylinder) - Ford Truck Enthusiasts Forums

 

GEM pinpoint test for power

 

Here is a link to a GEM teardown if you choose to take that path, which I gathered from the Tech Folder.

Link: https://www.ford-trucks.com/forums/1...l#post17383916

 

@BWST, you, sir, are a gentleman and a scholar. Two minutes in this morning, thanks to you, I discovered underhood fuse 101 (for the ignition switch on my Excursion) is blown. That likely explains the sudden no-WTS, no-start I saw yesterday. Off to pickup 2-3 of those, as it may blow again if the switch is bad.

Thanks man!!

Mark

 

thank you sir for this video.
that is where I ran into a question , getting the fuse panel apart .
the gem looked fine inside , so I now know I can maybe find my issues .
love this site .

 

FWIW just went thru similar on my 2001. Had a windshield installed in late 2023 and this made it worse...

Very little signs of water inside fuse box, but random gem related issues...only after exposure to rain, or washing.. (Relays clicking, vacuum pump coming on, abs dinging while driving, blower motor staying on after truck shut off.)

Finally found a competent glass guy familiar with these trucks in particular. He could not pinpoint a leak, but pulled, cleaned and installed new glass per my request.. Once he pulled windshield there were two areas he thought, could be a maybe.
My symptoms are now gone.

There is a company on ebay that sells fuse boxes refurbished for these trucks. I have one to install now that i got the leak fixed.

https://www.ebay.com/itm/254359911068

 

Progress made, but now I need to understand why:

Thanks to@BWST , I found maxi-fuse 101 (in the underhood fuse box) blown this morning. It's for "Ignition Switch (B1 & B3)", according to the manual. That resolved the radio and overhead display issue that occurred at the filling station yesterday, but still no WTS light, or start, and Forscan, of course, couldn't connect to the PCM. Then I noticed that fuse 116 "Ignition Switch (B4 & B5)" was also blown. Replacing it brought back all remaining functions, and the truck started fine. Several codes showed up:

B1201 - Fuel sender circuit failure
B2425 - Remote Keyless Entry Fault (and I see this one often, including the start immediately before the filling station visit, but the keyless entry has always been flawless)
B1359 - Ignition run/accessory circuit failure
B1302 - Accessory delay relay circuit failure
B1371 - Interior Courtesy Lamp Relay circuit failure

None returned on a couple of starts after clearing them, but I'm not sure that means much.

I think fuse 101 blew at the gas station yesterday, but I don't know why. Fuse 116 blew while I was troubleshooting. Did I do something to cause that? Maybe, but I don't think so. They question is, why did either of them blow? Intermittently bad ignition switch? GEM issue? Something else, entirely?

I'm tempted to replace the ignition switch. They are inexpensive, easy to replace, and exist, none of which are true of the GEM. I could then pull apart and test my current one, and see if I can better understand if it was the issue.

What say you guys?

Mark

 

I would do what you suggest there. That's a good plan, and you'll learn more about your rig.

Can you post a pic of that manual page with that fuse information? I don't show that in the 2001 owner's manual I downloaded, but maybe that's for the pickup.