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Discussion Starter · #1 ·
And so it come to pass that the Excursion (2000, 7.3 has 4x4) was sitting in the driveway in the middle of the night.

Lo! -- it began to try and start itself. I rushed to the truck, threw up the hood, and disconnected the batteries -- and there it sat for two weeks.

A few days ago, I yanked the fuse box and GEM out and checked both for water intrusion. The GEM was fine -- corrosion free. The leads in the fuse box were not in good shape and it was clear that water had gotten in there and shorted things out which explained the Christine like behavior.

I disassembled the fuse box, soaked the leads in hot vinegar, neutralized, and then dried and reassembled everything. The connections were packed with dielectric grease (not on the connectors themselves) and the GEM was sealed with a light coating of silicone sealant. I spread a bead of dielectric grease on the mating surface between the GEM and the fuze box. The main fuse box connectors were packed with dielectric grease to cut off any path water might be able to take, and I spread a thin bead around the inside edge of the connector before I screwed it together. It's dry and as watertight as I can make it.

I will address the windshield leak that caused this later.

Prior to the repair:
  1. It was trying to start itself and, when wet, the HVAC fan motor wouldn't turn off.
  2. There was a sizzling sound under the hood when it was between start attempts
  3. The interior lights, windows, vents, and mirrors all worked
  4. It sat, untouched, with the batteries disconnected, for two weeks.
After the repair -- good:
  1. The truck no longer tries to start itself
  2. No sizzling sound under the hood
  3. The radio works -- aftermarket and may be on a different circuit
  4. The HVAC system works as expected
  5. The instrument cluster lights work
  6. I get a chime if I leave the headlights on
  7. The door locks work
  8. The truck drives as well as it ever did
  9. No fuses appear to be blown and pass a continuity check
After the repair - bad:
  1. No interior lights work (glovebox, dome, or courtesy)
  2. None of the windows work
  3. The rear vents do not open
  4. The power mirrors no longer work
I have no idea what's going on here. I've swapped relays around within the fusebox with no effect. I'm hoping that since I'm getting a tone when the headlights are on that the GEM isn't toast -- it seems to be working. There was no evidence of water intrusion into the GEM itself.

If I had to guess, I'd say there's some issue with a battery saver relay -- but that's a shot in the dark and since the radio works, even though it is aftermarket and installed by the PO, I'm not sure that's the right idea. I've swapped things around in the fuse box with zero effect.

There is a 20-amp fuse in the fuse box under the hood by the master cyl -- number 11 -- that was blown. That fuse is labeled as controlling the cargo auxiliary power point, but it's the only fuse I can find that's blown. I changed that out and there was no improvement.

The two relays in the in-cab fuse box, R1 and R2, are the power window relay and battery saver relay, respectively. Those two were nigh on impossible to remove from the fuse box when I was rebuilding it and on both, the caps came off while pulling out the relay. I'm wondering if I damaged them -- and I may replace both to see if that fixes things. I can't find a pinout for any of these relays else I'd jump them and see if I can get the lights on.

Under the hood is a 30A circuit breaker for the power windows. Any idea how long those take to reset? I disconnected the battery to give it some time to cool off, if that's how it works, and nothing changed.

Any thoughts on this? This one's real good and frustrating.
 

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Discussion Starter · #2 ·
Update: I've found that my Trailer Tow Battery Charge fuse was also blown -- it will be replaced shortly.

I checked the CB for the power windows and it has continuity.
 

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Bosch mini relay -- plenty of info on the web
terminal 30 is where power comes in and 87, 87a are the outputs
85 is coil ground and 86 is coil energize

you can jump from 30 to 87 as a test to simulate the relay
if the caps came off you can push the "flipper" to cause the contacts to close
 

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Discussion Starter · #4 ·
Bosch mini relay -- plenty of info on the web
terminal 30 is where power comes in and 87, 87a are the outputs
85 is coil ground and 86 is coil energize

you can jump from 30 to 87 as a test to simulate the relay
if the caps came off you can push the "flipper" to cause the contacts to close
Thanks - I pulled all 5 relays from the fusebox in drivers footwell and tested them. They all pass a DMM test -- continuity on coil ground when unpowered and on the energized terminal when manually flipped.

That suggests that something is not triggering the relay -- or that the energized circuit isn't powered. I'll put a naked relay in there and manually trigger it, and see what happens.
 

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Discussion Starter · #5 ·
I've been going through the truck testing all of the fuses, that I can find, for continuity. So far, all good.

Apparently, there's a relay somewhere buried in or near the instrument cluster that might be a problem -- any idea where that might be?

Failing all of this, what else could it be?
 

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Does manually operating the Accessory Delay relay bring the system online?
 

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Discussion Starter · #7 ·
Does manually operating the Accessory Delay relay bring the system online?
Manually triggering the Accessory Delay relay did bring the windows back online, but not the interior lighting.

I put a naked relay in the R2 "Battery Saver Relay" socket. When I manually triggered this relay, everything came back online; windows, mirrors, dome lights, -and- the Accessory Delay relay was energized. Wherever the fault is, it's along the circuit powering the battery saver function.
 

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That is in the instrument cluster
Hmm, ...not sure what year they moved that control to the instrument cluster
you are in that time period when things changed -- so before or after that is the question

@NoRalPh may know the specifics, I do not have a diagram for the 2000 model year
 

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Discussion Starter · #9 ·
Thanks.

The R2 relay that I triggered manually is listed as the Battery Saver Relay in the fuse panel diagrams I have seen. But, something should be energizing it - and that’s what is failing.

I’ve tried two relays here, so I’m certain that there’s not a problem with the relay itself - but the energizing circuit. You’re saying that’s likely originating in the instrument cluster?
 

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Discussion Starter · #10 ·
Well - I had two bad relays.

I plugged a naked relay into R2 and measured the voltage between terminals 1 and 2. It was 12.7 volts - so it should have been energized

I plugged an another naked relay into R2 and measured the voltage on 1 and 2 —same thing, 12.7 volts. It should have been energized.

I plugged a new relay into R2 and everything worked perfectly. All lights on, all functions working perfectly.

The problem appears to be solved!

I’m going to put new relays in all 5 slots to head off any other gremlins.
 

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Glad you got it figured out, sorry I was not as much help as I could have been -- just dont have enough of the wiring manuals
 

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Discussion Starter · #13 ·
I sincerely appreciate the help. You pointed me in the right direction on a difficult problem - and that was invaluable. Thank you.
 

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Discussion Starter · #14 ·
769233

If you’re building a library of diagrams, here is what I could find on the 2000 Ex showing some of the connections between the GEM and the fuse block and relays.
 

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Yes, thank you that will be handy
 
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