Bad Blower Problem

[cordes]

For the last couple of years I've had a problem with the ignition switch in my 90' Shadow becoming VERY hot when the blower motor is turned on. Much more than the low or M1 setting and it will get hot enough to burn you if you touch it right near the connector. I'm at a loss as to what the problem really is. Here are some wiring diagrams and a picture of some deal which isn't included in them. If they don't show up for you like they don't on my computer just open them into a new tab or window and you'll get the full size diagram which is easy to read. The problem is the same with or without the deal in line with the blower. I wouldn't think that just the blower would cause this much trouble though since it doesn't do it when I use the rear window defogger or the power windows.

http://www.turbo-mopar.com/forums/photopost/showfull.php?photo=16362

http://www.turbo-mopar.com/forums/photopost/showfull.php?photo=16364

http://www.turbo-mopar.com/forums/photopost/showfull.php?photo=16363

http://www.turbo-mopar.com/forums/photopost/data/500/medium/IMAG00031.JPG


I need to pick up an ammeter so I can see how many amps the blower is drawing.

[135sohc]

undersized wiring and bad contacts. I've seen it before on other P bodies, I guess we wernt good enough to get a relay and proper wiring setup like the other cars.

[cordes]

undersized wiring and bad contacts. I've seen it before on other P bodies, I guess we wernt good enough to get a relay and proper wiring setup like the other cars.

Where would you consider the wiring to be undersized? It's only having trouble at the ign switch. I've spoken with my dad about the problem and he suggested I cut to the chase and relay it too. I would really like to fix this if I can though.

[135sohc]

I'd have to look in the manual since its been awhile. I just remember something about that whole setup that was screwy and seemed marginal in design (besides lacking a relay)

Going through and cleaning all the connections really good and making sure the blower motor isnt going bad like a sticking bearing, full of dirt/leaves or anything that could be letting it draw more amps than necessary would probably work wonders for it though.

[cordes]

Yeah, I'm thinking that I could clean everything up. I don't know that the motor even spins on the lowest setting any longer, but the resistor tests good. I'm just surprised that it can draw enough amps to kill the switches and not blow the fuse.

[supercrackerbox]

It does have the correct fuse in there, right? Just something you might check in the mean time; I'd rather have blown fuse than a torched car.

[cordes]

It does have the correct fuse in there, right? Just something you might check in the mean time; I'd rather have blown fuse than a torched car.

Yes, it's the correct 30 amp fuse. I've got most of it pulled apart right now. If I don't come up with anything glaringly apparent when I pull the dash out to do some work on the HVAC box I'll just relay it.

[cordes]

I went ahead and installed the relay today. It's working flawlessly. I think the blower was just pulling too many amps for the ignition switch.

[A.J.]

I have a customer with an Omni have his blower motor switch heat up like mad when he turned it on. It turned out to be a bad blower motor switch. Your ignition switch might be on it's way out.

A.J.

[cordes]

I have a customer with an Omni have his blower motor switch heat up like mad when he turned it on. It turned out to be a bad blower motor switch. Your ignition switch might be on it's way out.

A.J.

It's definitely the blower which kills the switches. This is the 3rd(?) switch I've had in the car since I've known of this problem. It only effects the two wires for the blower motor too. There's just too much resistance there at the switch and it's killing them internally.

Worst case scenario with the current setup is that the relay dies or the motor gives out on me leaving me with no heat rather than with no heat on the side of the road because the switch is dead again.

[zin]

Are those capacitors in-line with the wires?

Seems odd to me, and a cheap/potentially dangerous design to pull a full 30amp load through a switch that will see heavy use, and doesn't seem to be any more heavy duty than those that did get a relay... Bean counter strikes again me thinks!

Mike

[cordes]

Are those capacitors in-line with the wires?

Seems odd to me, and a cheap/potentially dangerous design to pull a full 30amp load through a switch that will see heavy use, and doesn't seem to be any more heavy duty than those that did get a relay... Bean counter strikes again me thinks!

Mike

Yes, the caps were inline with the wires. I figured that's what they were. I definitely think it's a cost saver. It's the same deal with the headlights through the headlight switch. My plug for the headlight switch has been melted to the point that I can't believe it works. I'm thinking about relaying those next.

[zin]

It's the same deal with the headlights through the headlight switch. My plug for the headlight switch has been melted to the point that I can't believe it works. I'm thinking about relaying those next.

They'll definitely be brighter if you do!

Fortuitous timing, the dash is out of my Omni right now, good time to make these upgrades!

Mike

[cordes]

They'll definitely be brighter if you do!

Fortuitous timing, the dash is out of my Omni right now, good time to make these upgrades!

Mike

Indeed.

I actually had a problem today which was a real downer. Once I put everything back together I noticed that the dash lights wouldn't work. I traced it down to the wiring from the fuse block to all the dash lights. Obviously some sort of short in there. I had to pull the whole dash again, and I'm now in the process of seeing what I want to keep light wise. I could find no damage to the wiring, but there was still continuity between the power and ground. I think the last bulb I removed from the center column of the dash was the culprit. This car doesn't need much otherwise I would have investigated a little further before I started removing things from the equation the way I did.

Worst case scenario now is that I have to splice in a couple lights for the factory boost gauge etc.

[cordes]

I'll finish this thread off by stating that I had no further problems after this initial fix. I have just retired this car so that'll be the last of the problems I could have with it.