Carbd84

Title says it all. I pulled into the driveway after work last night and noticed smoke coming from the pass side vender vent. I grabbed the fire extinguisher I keep in the car and opened the hood. The fire was small, localized to one small wire harness. I put the fire out before it could spread to my fuel lines which were right next to the fire. I am now trying to find out what this harness is for, in the harness was a 3 wire connector, it appears to have been round, but its hard to tell since it melted. This harness is located right next to the hvac box and comes out of the harness that goes down to the starter then runs down into the pass side fender vent area. Ive looked on all-data and my repair manual, but I cant identify anything since its all crispy. From what I could tell with my ohlm meter one of the wires in the harness is a ground. I didnt take any pics last night and I am currently at work, but I will post pictures when I get home.

Any help is greatly appreciated.

Edit: looking at the wiring diagrams and component locations that I have on All-Data it might be the wiring going to the "electronic spark control module." Is that module mounted near the pass side hood latch?

Dt86

Man I'm sorry that happened! Glad you caught it in time and it didn't cause more damage.

KYC4

Dang! Sorry to hear this but thankfully you caught it in time!

Later,

Lee

ccrazor

The ESC module is mounted on the blower housing, 6E2-90 of the FSM..

Carbd84

Okay thanks. I will start taking things apart when I get home and see exactly where these burnt wires go to so I can replace the burnt harness.

Yet another setback on my cam break in...

Dt86

Not sure if it's what you need but check the parts thread. There's an 84 wiring harness for sale in it.

Carbd84

Thanks but I have it handled. I have about a mile of wiring of assorted colors and all the tools needed to just make a whole new harness if I wanted. Wiring up Haltech ECUs in race cars has given me plenty of experience on harness building. Guess it was stupid of me to trust a GM factory harness that was assembled in 1983...

JD Shredds

I'm really glad for your safety (and the sake of the car as well) that you keep that extinguisher on hand! That could have gotten really ugly. Just last week I saw what can happen with an engine fire as I drove by an emergency, and it wasn't pretty.

Dt86

Lol no prob

ccrazor

From 8A-25 there is a dk blue wire to the knock sensor, a brown wire to grnd. G129, a pnk/blk to both ECM and ECM/IGN fuse and a black wire to the ECM..

Carbd84

Hmm, I thought one of the wires was red, but I could be mistaken. I will check again when I get home from work and post my findings.

Carbd84

Okay so I'm home from work and ripped apart the harness that melted. It for sure doesn't go to the ECS module. The wire colors on the side of the harness that goes into the fender vent area are pink, red and green. The pink wire may have been orange, its hard to tell with how hold the wire is. The green wire I found went to a big connector that looks like it may have connected to the heater control valve, which is long gone. So I'm not worried about the green wire. The red wire is rather large and splits off and runs on its own down below the blower motor. The pink (maybe orange) wire also splits off in its own direction and appears to go down to the washer fluid tank along with a black wire that isn't part of the harness that melted, so I am thinking that pink (orange?) wire goes to the washer pump.

Here you can see the pink(orange?) wire and the red wire in question. You can also see how the fire melted half of my Hvac box.


Here is what remains of the connector and harness.


More bad news, I lost my damn FSM... and I can only access All-Data from work. So any help identifying the two wires in question would be greatly appreciated. Repairing the harness is going to be fairly easy. I'm just going to cut out the melted stuff and splice in new wire of the same color and gauge. The big red wire is going to be simple enough, but I cant I.D. what wire that pink(orange?) wire connects to on the other side of the connector. One of the wires appears black and has a splice into it a few inches down from the connector and the other appears to have been brown, maybe tan, maybe orange? Its so melted I can't really tell.

Again, thanks for any and all help, and thanks to those that are glad for the cars safety. I would push this car out of a burning building if I had to, so I'm glad the damage is "minor" when compared to what could have happened.

ccrazor

Is your high speed blower relay ok or did it get burnt, it has a 12 awg red wire that comes from a splice to a 10 awg wire.. There is also a16 awg orange wire to the relay as well as a 12 awg dark blue, a 12 blk/red, and a 18 awg black.. The washer pump has an 18 awg pink wire and 18 awg black going to it..

Carbd84

Thanks! You've been a great help! That solves where the wires go to. Now I just have to figure out which wire the pink wire goes to on the other side of that connector. Hopefully I can open up the harnesses more and find some insulation that isn't discolored. The only thing that got burnt in the fire was that one 3 wire harness and now there is a huge hole in my hvac box. Everything else seems okay. I'm going to replace all the fuel lines that were around the fire just to be safe as well.

ccrazor

If it helps the pink wire to the washer pump comes from pin 7 of the the wiper motor, top connector left pin..

Paul Workman

It appears to me you are in luck - the fire source is apparently centered around that connector. It is very common when a connection becomes corroded resistance builds up and if there is current flowing through it, then HEAT is the result!

So, my guess is after you replace the connector, you'll be golden. Oh, just be sure to use a new weather pack connector, some dielectric grease on the contacts is always a good idea, and poking some RTV into the wire entry holes of the weather pack (for insurance) might be a good idea (EXCEPT for the O2 sensor!! They depend on outside air to work properly...ask me how I know!)

Carbd84

Yeah taking a step back and looking at the situation while not in a panic, that connector was for sure the cause of the fire with the amount of corrosion in it. Looking at more wiring diagrams on All-Data I also know which wire itself caused the issue, the red high speed blower motor power wire. The other two wires in that harness were dead.

One of them being the wire going from the A/C pressure cycling switch to the a/c high pressure cut-out switch. I removed the A/C and thought I had gotten rid of all the wiring for it, but missed that one apparently... no way power could have been running through it.

The other being the power wire that runs from the wiper motor to the windshield washer pump. Both of the connectors on the wiper motor have been disconnected ever since the motor was back in for the second time after getting receiving the incorrect torque converter. My roommate decided to set the engine in the car by himself and destroyed my wiper motor so I just didnt plug it in and won't until I replace it. So that wire was dead, no power could have been running through it.

So since that power wire for the high speed blower relay comes straight from the junciton block, there should have been an inline fuse that would have prevented the fire. That connector getting hot and all the resistance from the corrosion would have caused that wire to draw enough amperage to pop a fuse before a fire would have started. Tonight when I get home from work Im going to check to see if there is an inline fuse blown.

Then its time to start repairing the harness...

ccrazor

That red wire comes from a fusible link on the starter that branches off to the alt. 3.0 red. The 5.0 red feeds the hi-blower relay but also goes to instrument panel and ignition, theft deterrent control module and fuse panel, from 8A-11..

desertmike1

It looks like you have this under control.. I think you taught all of us the importance of carrying a fire bottle, I may have to look into this.

Paul Workman

NOT necessarily! The fuse or a fusible link will blow only if the current exceeds the (fuse) value, but even during NORMAL current draw - substantially below the (fuse) value can and does generate enough HEAT due to resistance build-up to melt the plastic, and eventually ignite it. I.e., enough heat to cause a fire can be generated w/o current exceeding the (fused) limit...as you now have first-hand evidence of. Just sayin.