Electrical issues! Caddy -88

[nokivasara]

My dadīs Caddy almost went up in flames today, smoke poured out from the middle of the instrument panel!
Iīve helped him trying to figure out what happened and this is where we are right now:

1 The heater blower (fan) quit working just before the smoke.

2 We pulled out the fan switch and noticed that two of the wires had burnt.
Thereīs 4 wires to the switch, Yellow, Yellow/black, White, Red/Black.

3 The white and red/black wires had melted at the plug.

4 Thereīs no voltage at any of the wires at this moment. There should b 12V in one of them, right? Which?

I suspect that the switch itself is to blame, Iīll try to pry it open and take a look.
But i need help with which of the 4 wires is supposed to be hot, so I can get the fan running by installing a piece of wire and jumping the pins.

He really needs the fan to keep the windows clear, itīs winter here

[clbanman]

Edited to clarify:

In the interests of getting fan function back as soon as possible, I would not mess with the factory wiring right now.  Get two jumper wires (one must be fused and I would recommend putting a switch in it as well) and test your blower motor first.  Fused/switched wire should go to power.  The other wire should go to a tested good ground. If it doesn't work or blows the fuse, the motor is causing your problem.  If your existing wiring was all original, the problem should have blown a fuse.  If the blower works without blowing your test wire fuse, you can at least run the fan while you sort out the cause of your short/overheat and repair the wiring.

[nokivasara]

Thanx for the quick reply! I have been out again, I took the wire to the cigarett lighter and tried to get the fan going by jumpin the swich. Bad idea, nothing happened except it smoked a bit :lol:
So now I know the short is somewhere between the fan swich and the blower motor.
Iīll test the motor tomorrow, itīs getting really dark and cold now! Why do I need 2 wires? Canīt I just take one wire and use the motors own ground wire?

[somolovitch3]

Idea of two wires is to remove any possability that the ground is part of the problem.

Not to sure how an '88 is wired different from an '81. In my '81, the resister pack is located on the passanger side in the airway duct. Check and see what's up with that.

From what your last post said, the blower it self might be the problem, not the wireing. That is why the two wires to the blower motor its self.

Good Luck

[clbanman]

I have found that using factory schematics doesn't always work, because often a P.O. has modified or added wiring.  Going back to absolute basics and simplifying the circuit is often needed to eliminate problems caused by someone changing things around.  My current car has had the wiring hacked and butchered, and to save time and trouble I am completely replacing problem circuits as I come across them.

[nokivasara]

It was an intermittant fault in the motor, donīt know what 'cause I donīt know how an electric motor works, but it ran slower at times. Just like dragging brakes. Then it would speed up again.

The wiring turned out to work, I had missed a blown fuse in the darkness yesterday :oops:
I suspect that the drag from the motor caused the wires to get hot and that wvwntually blew the fuse.

[somolovitch3]

Sounds like new blower motor time, or at least get that one out and lube up the bearings. Use a light oil, start with WD-40 for to clean and lube, then use3-in-1 sewing machine oil, or the stuff for swamp coolers.

[nokivasara]

Changed the motor and now it runs as good as new.
Is the motor supposed to come apart just by removing the clip on the backside of the shaft?