Author Topic: Fan speed resistors... (Read 5875 times)

Trimster · « **on:** July 20, 2007, 10:18:39 am »

I have hi fan speed but no low or med. on my '83 Caddy. Me thinks the fan speed resistors are toast. Where are they located? and does anyone know their resistance in Ohms?

TIA

Northern RD · « **Reply #1 on:** July 20, 2007, 10:33:20 am »

Is there a big fat wire-wound resistor on the fan itself?

jtanguay · « **Reply #2 on:** July 20, 2007, 11:04:11 am »

low is only for a/c (which does use a resistor located on the rad fan), med & high are built into the fan itself. maybe your fan is pooched???

try jumping the wires on the fan thermoswitch (remove the connector on from the lower rad to do this)

Trimster · « **Reply #3 on:** July 20, 2007, 01:39:17 pm »

OOps... my bad. I'm referring to the heater and air cond. fan in the dash. The dash switch has off, low, med and hi. Off and High is all that works.

bob

jtanguay · « **Reply #4 on:** July 20, 2007, 08:38:33 pm »

oh... not sure of the ohms for the resisting... i wish i could find my resistor.

i've heard of the actual contacts for the fan switch to go bad though. you could try to jump the connections and see if that works.

MacGyver · « **Reply #5 on:** July 22, 2007, 10:15:15 am »

The resistor pack is in the heater box, sorry can't be more specific than that without seeing one. In my previous Jetta it was under the dash, never worked on the heater in a caddy.
Often what happens is the thermal fuse in the resistor pack pops when the fan bearings get a little tight & the current goes up.
Make SURE your fan motor is in perfect working order before you replace the fuse or resistor pack. Get the same value fuse from your favourite electronics parts place & solder it in if that's the problem.
I rebuilt a resistor pack for a friend yrs ago, can't remember the values. I know we read them off a good pack, and I bought new resistors from Electrosonic for a few bucks.

blkboostedtruck · « **Reply #6 on:** July 30, 2007, 03:57:11 pm »

yes on the passenger side near where your passengers toes will be theres a circuit board that has 2 philip screws and that is the fan speed circuit board only A/C equiped models have that circuit board ! you either need to repair your old one with new resistors! or find a good working used one! i think they are a obsolete part i have not found new replacements yet! well good luck
thanks Duane

burn_your_money · « **Reply #7 on:** July 30, 2007, 06:02:31 pm »

If your truck doesn't have AC then they are in the rain tray. It's a big white cylinder

Trimster · « **Reply #8 on:** August 06, 2007, 05:39:13 pm »

I have AC. And I have the resister unit in my hand. I am puzzled by the low tech 'hair dryer' approach to resistance and control. But KISS is fine.

All my coils are in good shape. There is, however, a thermal couple right in the middle of these babies that I think is suppose to blow if the fan quits. On a hair dryer they use a thermal switch that resets it's self. would be nice in this unit.

So, all resistances check out, but the thermal couple is open... no electrons through this baby. I'm searching for a replacement. They are a common item... just need to locate a suitable sub. When done, I will post a tech article on these units and how they can be fixed/rebuilt.

Trimster · « **Reply #9 on:** August 07, 2007, 10:38:55 am »

Ok, hot on the trail of the thermodisk thermocouple. Anyone have an idea what temp these should trip at? It seems to me that if we are pushing 180 water through the heater core, the trip temp has to be above that. Maybe 200 F? It has to be above the highest air temp created by the hot water exchange but below the point where it could cause a fire under the dash.

If someone has access to electronic parts databases , here's the info on the part case. Thermodisk, MicroTemp, 4300 A1, NTW1520.

TIA

somolovitch3 · « **Reply #10 on:** August 10, 2007, 04:24:32 am »

have you tried talking to Monty at Ra-Elco ?
Location is about 2800 South on Main.
Look them up in the white pages.

Trimster · « **Reply #11 on:** August 15, 2007, 10:51:28 am »

yes. what we need is the target heat range for the thermocouple. If we know that, then we can sub it. Any ideas?

bob

madmedix · « **Reply #12 on:** October 28, 2007, 11:45:11 am »

bump!!