Pre Emptive FIRE!

[Matt Wood]

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

[Gary Lewis]

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!

[Matt Wood]

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!

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

[ArdWrknTrk]

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

You might check there first.

[85lebaront2]

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

You might check there first.

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.

[ArdWrknTrk]

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.

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.

[Gary Lewis]

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.

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.

[ArdWrknTrk]

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.

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.

[Gary Lewis]

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.

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

[Matt Wood]

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

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