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Pre Emptive FIRE!

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Matt Wood

Pre Emptive FIRE!

Hi guys, in the process of putting the dash back together i thought id feel the big loom that runs across the top of the cluster... dont ask me why i did but it was lucky that i did!!! it was HOT, i don't think it would catch fire but id rather investigate the issue than wait for the inevitable. i have attached a picture of the area that is hot, its on the bend as it goes down behind the vents, the top doesn't seem to be hot.

I thought i would ask here before i pull the loom apart and find the hot wire as thats quite an involved job id like to try and avoid..

if anyone has any ideas of what looms run in this area that may be some help to ascertain what is going on. Just an FYI i have just finished installing a small amplifier for my already aftermarket radio but is still seems to get hot when its switched off so i dont think its that.

Any suggestions would be great, Thanks

'Shelby' - 1985 bronco XLT, 351W C6, Limited slip 9 inch

Gary Lewis

Re: Pre Emptive FIRE!

Administrator

Matt - Glad you caught that now!

As for what runs there, have you seen the new page I added yesterday: Documentation/Electrical/Wire Routing? See the Main Wiring tab, which has an illustration of the back of the instrument panel.

But there are a LOT of things that run there. Everything that goes from one side of the engine compartment to the other goes through there. For instance, the yellow wire that is shown as "37 in the schematic below runs there. (I know you have a Bronco and I'm pretty sure you have gauges, but this schematic shows that wire better than the other one does.) It goes from the starter relay to just above the steering column on the engine side of the firewall. If you have an aux battery or the trailering package you'll have either a relay or a junction block there. Anyway, check to see that that wire isn't pinched or shorted somehow.

The right side headlight wires go through there, as does power to the A/C blower switch. Basically anything going to the right side of the vehicle.

I would pull the fuses and see if one of them solves the problem. But if not then I'd pull the fuse links off the starter relay, one at a time and see if one of them solves the problem.

Good luck!

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Matt Wood

Re: Pre Emptive FIRE!

Thanks Gary, ill give pulling the fuses a go tomorrow and see where i get to, that will at least tell me what circuit is causing the massive current draw.

Ill update tomorrow

Cheers

'Shelby' - 1985 bronco XLT, 351W C6, Limited slip 9 inch

ArdWrknTrk

Re: Pre Emptive FIRE!

Administrator

In reply to this post by Matt Wood

The brown instrument illumination wire coming from the light switch is a known weak link and has meltdowns.

You might check there first.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

85lebaront2

Re: Pre Emptive FIRE!

Administrator

The brown wire is the parking/running lights and on cab and chassis or heavier trucks with roof lights that wire has been know to destroy the light switch, The DRW trucks use a relay and separate feed for the fender and rear clearance lights.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

ArdWrknTrk

Re: Pre Emptive FIRE!

Administrator

I suppose you're right Bill

If it was mine I'd put my inductive ammeter on each wire in turn.
Something is pulling serious current.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Pre Emptive FIRE!

Administrator

Matt's 5 hours ahead of you two, and 6 ahead of me. So we can give him a few more ideas to kick around.

I'd suggested pulling the fuses and pulling the fuse links. But you are right, Jim, something is pulling serious current. And just checking the heat isn't a very scientific way to test.

I think I'd be inclined to pull the fuse links off the starter relay first and then test from each fuse link to the relay with a test light. With the doors closed so there's no dome light, and assuming he doesn't have an underhood light, he might get a dim glow off the main fuse link for the radio's keep-alive circuit or the clock. But it shouldn't come on full brightness if it is an incandescent test light.

If he has one that lights it fully then that's where I'd start investigating. If it is the main feed to the fuses, then start pulling them and testing.

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Pre Emptive FIRE!

Administrator

I really would like one of those FLIR cameras for my phone.

You could pretty much tell at a glance what's going on with the dash opened up like that.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: Pre Emptive FIRE!

Administrator

That's a GOOD idea! You'd know which circuit it is immediately.

Gary, AKA "Gary fellow": Profile

Matt Wood

Re: Pre Emptive FIRE!

so... i decided to just take the dash apart and strip down that loom because i had decided that i knew what wire it was, and that i just needed to see the colour... i was right with what wire it is, now i just need to find out what that wire does. this wire looks RED with a Green trace, it loops back on itself in that loom location and i cant tell where it goes. Any insight would be great,

Thanks

'Shelby' - 1985 bronco XLT, 351W C6, Limited slip 9 inch

Matt Wood

Re: Pre Emptive FIRE!

So after looking at the evtm it seems that that wire could do a lot.... would I be right in saying it's this, red and green wire shown in this screenshot?

'Shelby' - 1985 bronco XLT, 351W C6, Limited slip 9 inch

Gary Lewis

Re: Pre Emptive FIRE!

Administrator

In reply to this post by Matt Wood

Matt - I can't find "r/g" as wire colours. Nor "r/dg" for dark green. But I do find several instances of "r/lg". And here's one. But you'll notice it isn't served by a fuse, just a fuse link. So one approach would be to pull all the fuses and see if it still gets hot.

But that wire doesn't make sense as I don't think it goes up there.

More likely is this one that supplies the sense circuit to the alternator. It would go from the ignition switch up over there, to the right side, and then out to the alternator.

But there are others, so if this doesn't work let me know.

Gary, AKA "Gary fellow": Profile

Gary Lewis

Re: Pre Emptive FIRE!

Administrator

In reply to this post by Matt Wood

No, I think it is the red/light green wire in my pic.

You beat me. Well done! Want to know how I did it by searching?

Gary, AKA "Gary fellow": Profile

ArdWrknTrk

Re: Pre Emptive FIRE!

Administrator

In that case it would be easier to unplug (un-shoe?) the coil than to detach the fuse link.

Coils get really hot once they're saturated and the ignition is left on.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

ArdWrknTrk

Re: Pre Emptive FIRE!

Administrator

I've always said the resistor wire is pink.

I keep getting corrected...

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Matt Wood

Re: Pre Emptive FIRE!

In reply to this post by Gary Lewis

so... after much aggravation removing the dash i have discovered that it is in-fact the resistor wire lol, if i had looked a little closer when taking the first picture i would have seen that it says it right on it haha, but oh well for my own peace of mind im happy i stripped it back to find out. also gives me a good opportunity to clean the inside of the dash

'Shelby' - 1985 bronco XLT, 351W C6, Limited slip 9 inch

Gary Lewis

Re: Pre Emptive FIRE!

Administrator

LOL! Well, live and learn. So, can you mark where the ends of the resistor wire are? Lots of people have asked and you are the only one I know that has found it. So mark it and take a pic?

Gary, AKA "Gary fellow": Profile