I've got no low and medium fan speeds, just high and extra high. I know there's a resistor or something back there thats at fault. Anybody know which one?

use Search? :D

Anyway - there is a resistor.

Some older trucks only had 3 speeds (I think)

On my 1989 - its located on the duct under the glove box - you can get to it w/o removing anything. Follow the wire(s) that plugs into somehting that bolts/screws into the duct for the air vent.

On an older 1985 that CAZ and I took apart - it was tucked closer to the blower motor. Looked like it might be a PITA to get at there (at that point we had the entire upper dash removed so it really wasnt an issue of getting to things)

Dealer has em - I think $20 or less.

Its a "thin wire" resisitor.

On another bboard we had a discussion of the resistances and the wattages dumped out of the "thin wire" and what those resistores woudl cost - it was a neat idea for a project - but would cost alot (but if ya think about it - maybe ya only need to redo the lower 1 or 2 settings - so mebee it wasnt too much)

I wrote the ohm readings down somewhere....

EWong

Originally posted by EWong
use Search? :D

Anyway - there is a resistor.

Some older trucks only had 3 speeds (I think)

On my 1989 - its located on the duct under the glove box - you can get to it w/o removing anything. Follow the wire(s) that plugs into somehting that bolts/screws into the duct for the air vent.

On an older 1985 that CAZ and I took apart - it was tucked closer to the blower motor. Looked like it might be a PITA to get at there (at that point we had the entire upper dash removed so it really wasnt an issue of getting to things)

Dealer has em - I think $20 or less.

Its a "thin wire" resisitor.

On another bboard we had a discussion of the resistances and the wattages dumped out of the "thin wire" and what those resistores woudl cost - it was a neat idea for a project - but would cost alot (but if ya think about it - maybe ya only need to redo the lower 1 or 2 settings - so mebee it wasnt too much)

I wrote the ohm readings down somewhere....

EWong

As a former electronics tech I would never pay over $1 for a resistor. Find out the value buy looking at the colored bands and go to radio shack...

Originally posted by pvonburg


As a former electronics tech I would never pay over $1 for a resistor. Find out the value buy looking at the colored bands and go to radio shack...

Except that it's not discreet resistors, but open coils of wire each exhibiting some unique resistance, try finding color bands on that.

Actually they're more like little heating elements, which is why the assembly is mounted in the blower ductwork (on 1st gen trucks at least), to help cool them a little.

Measuring each coil of wire and substituting fixed resistors is possible, but the resistors would have to be high wattage power resistors (i.e., the wire wound type).

As I hinted at - this is so 1998

I posted the Ohms on a differnt list - I'll look em up sometime (I think I scrawled em in the FSM too)

The list at the time also agreed on the wattages each resistor had to "reject" and someone looked up high wattage resistors to meet the required specs.

They resistors may have been "mil spec" or something thus increasing the cost, but I think the consensus was that a more durable module could be made, but parts for it would cost more than the OEM part and you would have to make it.

THERE ARE NO GAY A/C QUESTIONS - A/C IS GOOD, I LIKE A/C:D :D :D

So it's by the blower, but what does the thing actually look like........besides a thin wire?

Well - its the only thing thats attached to wires thats smack in the middle of the duct.

OTH - on the 1985 I took apart - it was "on top of" the blower - I think you had to have the glove box out to see it.

Its a rectanguar piece of black plastic with a connector molded into the back that the wire plugs into. There is a 3 or 4 pin connector that goes to it.

Its held in by 1 or 2 phillips head sheet metal screws.

The thin wires are not visible until ya remove it.

The thin wires look like the loops inside a hair dryer - except they are coated with a stripe of some kind of ceramic coating.

The ceramic coating is to keep the loops "apart" so they dont touch.

BE CAREFUL if you decide to play around with the resistor with the blower on.

I manage to light a bunch o napkins on fire cause I had the resistor down on the floor. :emb4: Yes - it gets RED hot.

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Part 88635-89103
between L - M1 = 1.4 ohm
M1 - M2 = 0.8 ohm
M2 - H = 0.5 ohm

Nice, thanks!