SC heater blower wires caught fire again question

[ramonesfreak]

for the second time, i have had a mini-fire with a blower motor. im on my 2nd heater blower motor. the other day, it was raining very hard. start car, pull heat levers and immediately smell electrical burn smell. then in an instant it was gone and i thought i had imagined it...

tonight i notice blower is not running. i look and the brown wire without the stripe, is melted, crispy and broken in half and what remains of the wire has like a green oxidation coating on it. there had been a splice and i guess with the amount of rain, some water got behind the electrical tape and it got zapped

i guess what im wondering is, why didnt the fuse blow? i checked and the fuses are fine. there must be a simple answer for someone with knowledge of electrical stuff

i think i am going to leave my blower disconnected. enough heat gets in without it running. having had two problems involving sparks with blower motors, i would bet that the majority of engine fires involve the blower motor. luckily (twice) my engine compartment was not full of fuel vapors

[docrodg]

The green oxidation coating may be the key to your question. If the wire was corroded and brittle then it is possible that it got many of the strands broken, and had only a few holding it to the connector. These were not enough for the amps going through it and it heated up and melted.

[ramonesfreak]

thanks. can i get this wire at home depot or radio shack? is there a technical term for this type of wire ?

[Mysterytrain]

A picture would be helpful, check the fuse size it should be 10 amps. Radio shack might have the correct gauge wire but you really should also match up the color. Eagle Day has a good selection of OEM style wire. I think he even has the connectors.
http://eagleday.com/elparandtool.html

[stevemfr]

Originally Posted by srandallf

i would bet that the majority of engine fires involve the blower motor

Had to smile on that. Not really. I'd bet that there are very few 911 engine fires attributable to the heater blower.

The Bn wire is a ground. The reason the fuse didn't blow is that your heater blower wasn't drawing more current than it's supposed to - as with a short. You just had a bad ground and all the current going through the motor was then trying to go through whatever the problem area was. The problem area acted as a resistor and got very hot.

Replace the ground wire. You can either continue to follow the wire down the harness to a ground point, make sure it's in good condition, and splice to that (solder or quality crimp connectors - sealed to prevnt oxidation) or run a parallel gnd wire. Let the blower run a couple of mins. and make sure all is well.

The wire is automotive wire (multi-strand, not single strand house wire). Do use the same color.

[ramonesfreak]

fuse size is correct. i always replace fuses with correct fuse

thanks for the link..i see they have various selection of wire...for different amps...not sure which to buy. should the amp rating be dictated by the fuse?

http://eagleday.com/neauwi.html

[ramonesfreak]

Thanks for the explanation Steve

[ramonesfreak]

Stopped by Radioshack and picked up some 12-gauge hookup wire. The technical date printed on the spool says : 600v, 80C, 1/32PVC, stranded

will this be ok to use as the ground wire? There is no mention of amps

[docrodg]

12 gauge is more than ok for 10 amp. 80C is temp rating... seems that should be fine as long as it isn't against the exhaust. Stranded is perfect, gives it flex. 1/32 PVC is jacket on it, that should be fine as well. Now hook it up right... sealed connectors if they must be used, but straight replacement of the old one is better, and clean that ground point and put a little vaseline or similar on it to prevent corrosion!

[ramonesfreak]

Great! thanks alot

[ramonesfreak]

i hooked fan back up. let fan run a minute or so. works fine but both positive and ground wires get pretty warm

is that normal?