Thought it was a bad fan switch.....

You have a burned out resistor pack.

It is in the heater box in the passenger foot well just above the fresh air vent.

They are cheap and easy to change.

When blown, only the high works because it doesn't use any resistors.

Mike

snipped-for-privacy@columbus.rr.com wrote:

Hey thanks Mike. Great diagnosis. Can you explain that a bit better...there is a part of my unit that is missing...it is the box in the passenger side that covers the actual heater motor...has some vents on it. I've noticed something strange though up above the heater motor...has what appears to be a coil of some sort...like you'd see in an electric heater..with wires attached to it. Does that have anything to do with it? I'm a bit confused what I'm looking for...part and location. Thanks! Allen

incompatable???

Very nice description...but now I'm really lost! What IS that picture of? I can make out a speaker...okay it was marked. But none of that looks familiar. The resistor block assembly looks like simply the end of a plug...which I'm not sure connects to what. Allen

better...there

It is inside the Jeep on mine.

What year is your CJ?

On mine it is dead center above the fresh air vent on the passenger side and has a 3 pronged plug on it with one brown and two black wires.

The resistors themselves do look like heater elements or light bulb filaments. They are just a coil of wire of different thickness'.

They heat up when the power is on low or two as they drop the power down to the fan. That is why they are inside the heater box, they need air flow or they will burn out.

Mike

snipped-for-privacy@columbus.rr.com wrote:

On or about Wed, 3 Dec 2003, snipped-for-privacy@columbus.rr.com of snipped-for-privacy@columbus.rr...:

I looked it up in the 4WD catalogue and they list the same 3-speed fan switch for 1976 through 1986, dunno what they went to after that. On the odd chance that AMC didn't change the heater design too much, the CJ resistor pack (to set the fan speed) is screwed to the heater box just above the vent outlet, above the passenger's right foot. The pack is a 1" x 3" piece of particle board with three wires running into it. If the connector has come loose you won't get lower fan speeds, and if the nichrome coils (on the other side of the mounting board) are toast you won't get lower speeds either.

Happy hunting.

I fixed the problem Lee, it was a rusty prong on the connectors. Sprayed some electronic cleaner in the plug and sanded the prongs and it works great!!! Thanks Allen

snipped-for-privacy@columbus.rr...:

incompatable???

Excellent news (any jeep fix that doesn't involve bleeding knuckles is a good fix).

A thought for you, though: Bulb grease can be your friend. If those contacts rusted once, they'll likely rust again. My CJ's old wiring harness once let out a fair bit of smoke and the only cause was rust at the hi/lo light switch. Just, you know, a thought.

On or about Thu, 4 Dec 2003, snipped-for-privacy@columbus.rr.com of snipped-for-privacy@columbus.rr...:

When I put the 'glass body on I hit every plug and socket with dielectric grease. They call it spark plug boot protector too.

I think one of the prongs on my resistor pack was really rusty too.

Mike

Lee Ayrt>

"(any jeep fix that doesn't involve bleeding knuckles is a good fix)." I don't think I can even look at a picture of my CJ without my knuckles starting to bleed...

"Bulb grease can be your friend." Does that stop the bleeding faster than normal grease?

snipped-for-privacy@columbus.rr...:

Yep, same here. When I put the Painful harness in I shined every piece of reused connector and greased every connection and bulb socket.

I'll bet that the rusty prong on the resistor pack is the one that gets hot anyway, just from heat spilling off the resistors. Heat makes it prone to rust, rust raises the resistance in the junction and it gets hotter still. One day it either stops working or starts smoking -- like my hi/lo switch did.

snipped-for-privacy@columbus.rr...: