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Discussion Starter #1
So I discovered a strange issue this morning. Haven't driven it in a week or so, this morning the batteries were completely dead. Charged them after work, and the radio and blower are on and will not shut off. No key in/on, they do not shut off when any of the doors are opened. It did this a few months ago when we had a cold snap; the last week or so it has been very cold here.

Would this be a failing ignition switch?
 

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Year and model would be helpful

Blower shuts off with the key -- radio is on another circuit that stays on until you open the door or it times out
 

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Discussion Starter #3
Sorry; 2001 F350 Lariat, 7.3L

Doing some searching finding references to a failed GEM module. Will check that tomorrow, see if it appears to have water intrusion.
 

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Because it's an '01,,,, you may/maynot have a GEM.

During the '01 run there was a major electrical upgrade. If your truck has a Trans Temp Gauge in the cluster, along with a Digital Odometer, your truck got that upgrade (like the '02's and above). If not, treat it as a 2000, for its electrics.

Upgraded systems no longer have a GEM (like an '02) otherwise expect to find a GEM on the backside of the fusebox (like a 2000).
 

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Discussion Starter #5
Great info - thanks!
Mine has no trans temp gauge in the cluster (PO added it to the A-pillar).

Since this has only happened when the temp gets cold, below 20*F or so, I'm going to assume it is a cold solder on a trace or component which loses contact. The radio and blower were not on when I parked the truck, they came on like magic when the temp dropped.
 

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Discussion Starter #6
Today was fairly warm, close to 50*F.

The radio is still on, but the blower is now off. The power windows do not work, but the driver's power seat, power mirrors, and the power locks do work.

There appears to be no water intrusion on the GEM or fuse box.

Is the GEM identifiable without removing it?? There is a small sticker on the side showing: NT8-14B205-P131 and 31431021466A52 but those don't seem to exactly identify it. I've read the replacement GEM model must match the current one exactly or it won't work.
 

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Can you disconnect the GEM and see if that shuts everything off?
 

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Discussion Starter #8 (Edited)
Checked it this morning and the radio is off.
Will be pulling the GEM tomorrow to get the model number, and clean all connections.

Power windows are non-functional, the key fob no longer works to lock/unlock, but locks do cycle using the interior button.
 

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Discussion Starter #9 (Edited)
Got it out; there appears to be no water intrusion. Fuse box has a small area with light corrosion where 1 of the large harness connectors attaches; currently dry.



Is there any way to definitively test the GEM? This one must be made of gold as most of the used GEMs are at or over $300.


The one I pulled was made in Mexico and has a mfg date of 04/07/20; assuming this is 7/20/2004 since the labels I've seen mfg in Canada have a 4-digit date.
 

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Discussion Starter #10
Sourced a used GEM and got it installed. No more funky electrical gremlins, but no power windows or dome lights either. Still no crank no start.

Bypassed the starter relay on the fender well, she fired right up. Assuming the relay is bad as it is an original Ford part.

Cannot find a bad fuse or relay to explain the windows and interior lights. Potentially the GEM will need a reflash??
 

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Sourced a used GEM and got it installed. No more funky electrical gremlins, but no power windows or dome lights either. Still no crank no start.

Bypassed the starter relay on the fender well, she fired right up. Assuming the relay is bad as it is an original Ford part.

Cannot find a bad fuse or relay to explain the windows and interior lights. Potentially the GEM will need a reflash??
OK a little confused by this part -- does it crank with the key?? or not -- I mean 'no crank, no start' means the engine is not turning and therefore is not starting

'fired right up' means you only get the engine to crank by jumping the relay?
 

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Discussion Starter #12
It did nothing at all when turning the ign switch to Start. No click, nothing.
I bypassed the starter relay using an 8ga wire across the large terminals, with the ign switch in the run position, and she cranked and fired right up. :grin:

I measured the voltage at the small relay terminal connector, 4.46v with switch in Off and Start positions. Checked fuse #20 again, and it was fried. I replaced the fuse, leaving the small relay terminal wire disconnected, fuse did not blow when cycling the ignition switch. I ran a jumper from the batt+ to the small relay terminal and the relay engaged and powered the starter. Reconnected the small relay wire and she fired right up using the switch. I've started her multiple times with no issues so far. Strange gremlin; I'm guessing the relay may have been stuck.

Still have no power windows or dome/cargo lights; fuses #7 and #14 are good. There may be differences in GEM features even though the part numbers are the same? Maybe needs a reflash?
 

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Jumping from the battery terminal on that real y to the small terminal should activate the relay -- good way to test the functionality of the contacts and coil. The voltage on the small wire concerns me, I would think it should be zero with the switch not in the start position. The blown fuse may be an indicator of a potential harness issue - it does not take 20 amps to engage the start relay, so either the fuse actually got overloaded, or a loose connection caused heat buildup in the fuse and melted the element.

I don't have a wiring schematic for your year -- would be glad to help you trace the wiring if I could -- @NoRalPh do you have a schematic?

Can you take the old GEM apart and look at the insides? Water damage can erode/corrode the traces inside, but oftentimes it is just a bad solder joint where the terminals connect to the circuit board -- you can reflow the solder -- everyone should learn to solder -- you can get a decent iron for less than 30 bucks

I am thinking it may be possible to repair your old GEM -- that one worked for many years
 

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Discussion Starter #14
I saw no water damage/corrosion on the GEM board. I figure it's a cold solder joint since the only time it had issues is during very cold conditions where the solder could shrink and lose connection(s).
Soldering is not an issue; I have a nice variable temp soldering station and a desoldering station. I do a bit of work maintaining/refurbing my analog audio gear, pinball machine boards, etc.

The GEM I pulled out I'm concerned with as it is the only one I've seen made in Mexico, every other GEM I've seen for sale are produced in Canada. Not sure if there would be an issue with the board, unless it were produced somewhere other than the Ford OEM mfg.
 

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Check your towing wiring harness. Mine caused lights to stay on, apparently how theyre wired leaves power always available, new truck end and i was good
 

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It did nothing at all when turning the ign switch to Start. No click, nothing.
So when this happens, the most likely issue is with the NSSW (neutral safety sw) and common to be intermittent and often indicated by a "sloppy" shift selector linkage (usually just lose bolts). Next time it does this try moving the selector Up , past P, or even N and try again.
 

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Discussion Starter #17
Thanks!
Hopefully no future issue with it. I moved the shifter around, plus moved it to N previously which had no affect.
 

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Discussion Starter #18
So another twist.

Truck is starting just fine, all seemed well using it yesterday. Got up this morning and see a blue light outside. The radio is on again. It was off when I parked the truck yesterday afternoon.

So, since the GEM was replaced and the problem persists, it must be something else. I assume the only other component which would be a potential source of this problem is the ignition switch. I guess I'll replace that, looks like they're ~$25 and easily accessible.
 

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Will be a rubbed wire ...somewhere -- causing a relay to engage
 

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Discussion Starter #20
I'm not sure about that; would that would cause an issue only when it's cold, after sitting for hours. The radio was not on at 9:30 or so last night, but on at 3:30am. Radio and blower were off when I got home this afternoon.

I replaced the ignition switch, cheap and easy replacement.
 
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