Hey Scotty,
I have a 99 Ford F150 XLT 5.4 4x4 "3dr" extended cab with 160,xxx miles.
Recently while driving the driver's window started rolling itself down, as soon as I'd roll it up I hit a bump then auto-down would engage again.
I got home, rolled the window up & shut it off, checked for codes....nothing.
NOW for the insanity. If I engage the driver switch in either direction the R1-R4 relays go bonkers, the dome light either gets brighter or just turns on, the entire heating/cooling system quit(it'll also turn on the interior lights while making an odd pitched whine or groan). You can hear the normal vacuum sounds of the system engaging but no blower motor actuation or any heat creeping out. This is the biggest safety issue since the windows ice up inside & I can't defrost them.
Another oddity that arose is the high beam & hazard indicators lit up but aren't engaged. The signals only work if my headlights are off & if I open the door, the dome light strobes about once per second.
All fuses seem to be intact, there's no moisture I can find in the dash or affected areas (I cleaned the inside of the cowl of any debris this summer & made sure water could escape properly), all seems dry. With it being below freezing finding any seems like it would be easier since it would be ice.
The only thing I can think of as a precursor was the driver windows auto down going too far & I'd have to stop it on my own.
Some say it might be the GEM, others the fuse block itself. I've seen a GEM bypass (for the windows only) with some cutting & splicing but I need to get the heat working, etc.
The 4x4 still works although it now grinds when engaging it at low speed. I also have to mess with the affected switches to disengage it.
Any idea what's going on? If it's the GEM can I bypass each component somehow?
This is a $700 stop gap truck until I can find something old(er) & decent in the $3k range, so I really have to avoid expensive parts eating into the replacement budget. The scrap yard & classifieds seem about as expensive as new parts.
I'm 100% comfortable hacking into the wiring/doing some bypassing as this clunker is getting 10lbs of tannerite in a large field once I'm done with it.
Thanks,
Russ
Before spending any money check all the grounds, including engine to body ground. A lose or corroded ground cause reek havoc on an electrical system.
Don't overlook the cooling system. With the radiator cap removed and the engine running, connect a volt meter, neg probe to ground and pos probe into the coolant. There should be no voltage reading. Again, if you coolant has taken a charge, weird electrical problems can occur.
Given the amount of rust(the only unaffected areas aren't steel), I'm sure there are some ground faults so I really need to check.
I never heard of the cooling system issue but I'll give it a shot while I'm at it. Is there any acceptable level or should it be completely charge free?
There should be no electrical charge on the coolant.
To try one of those bypass kits it's worth try a lot of times those module start going bad and it gets really complex
The Tannerite idea sound like the best choice. Entertaining and educational at the same time. Seriously, see if you can find a way to bypass all the relays to get current to what you want. Where I live. we're getting $83 per ton for scrap metal.
$83/ton, ouch! I think normally a car brings $400 as strictly scrap.
Seems like fused bypasses might end up being the solution if I can't find the culprit(s) in the next two days. It's the only time it'll be warm enough where I can sit in the parking lot without worry of it turning into an ice patch with cars not being able to stop.
"Recently while driving the driver's window started rolling itself down, as soon as I'd roll it up I hit a bump then auto-down would engage again."
That indicates 12 volts going to ground...intermittent short.
Start at window switch...look for partially melted plastic.
Work your way to the wiring pass thru from door to cab.
Undo fuse box and look on back side...its common to find a problem there with melted connections.
Until you find the cause, disconnect the battery. If you don't and hear the horn beeping in the middle of the night...watch the fireworks.
So far the window switches have all checked out, they were one of the first things I went after since I disassembled them/gave them a thorough de-ox during the summer while diagnosing a dead passenger window motor.
When I was going through that process I tried pulling the boots between the door & body to check for any bad wires....that was a little difficult as I've never seen seals that long....about 3-4" into the body instead of what I'm used to on older GM products. So that's rather difficult to compress/check the wires even after trimming all the excess rubber to make the wire loom partially visible.
As for the wiring in the door itself, any thoughts on removing all the factory loom/tape then rewrapping it or would that be overkill?
I'll have to pop the fuse box as you mentioned for further inspection, but the closest thing I've noticed to possible abnormal heat was on the R1 & R2 relay blades themselves. They have an extremely slight blueish discoloration you'd associate with stainless headers. Other than that, just a bit of warmth when they're going spastic when something trips them repeatedly.
Water from a leaky windshield can wreak havoc under the dash.
I'm saying its a fuse box issue...Relays are getting too hot if they have discolored.
Continuity check on door wires...unplug harness inside door and find other end under dash. Don't have to cut into loom. Open and close door while testing...wiggle test.
Good point.
Any saving the fuse box if water has gotten in? Absent physical damage I'm thinking maybe a bag of rice as desicant then spray it down with electronics cleaner.
I've never noticed any water or moisture during/after storms but I'll have to find some low temp curing sealer, If the windshield is leaking a good bead couldn't hurt, but the high temp will be in the low thirties for a while.
Almost forgot....I had to put in a new bulb a couple weeks back, I noticed some old RTV & rot around the high third brake light (that area likes to rot on these for whatever reason). There was some water getting in there.