callouie

This morning, it was absolutely freezing out, dash said 13 F. Blower inoperative on anything other than highest speed. I do a search, and it sounds like a resistor pack. I order up a new part from Roger, read up on the directions, and make my plan on how to attack the problem.

5 PM, hop in the car to go home. Oddly, the blower works just fine at all speeds. I turn the system off, set the fan to 1, and turn it back on. Airflow resumes, as though nothing was wrong. Some posts refer to a sticky/worn motor not being able to spin up at lowest speed, but this doesn't seem to be the problem.

I am perplexed on what this could be. Could cold temperatures cause some issue with the blower motor? The blower has been perfect up till now, and I can't figure out what would cause it to not work in the AM, but in the PM, when it's about 40 F, it worked fine. Should be in the teens tonight, so I'll have another whack at troubleshooting in the AM, and I'll have the resistor pack for this weekend, if that's the problem. My understanding was that the resistors overheated, causing problems, but with the low temperatures, it doesn't make a lot of sense.

Oh, and airflow is good, so I don't think it's the lack of cooling air causing the issue. I also didn't get the symptom of smelly electronics, as some people reported when their resistor pack died.

Rod Underwood

I just replaced the resistor pack in the 82. It would work only at high speed, "except" on cold days then it would work at all speeds, depending on how cold it was. It would eventually end up at high speed only.

Sounds like it might be your problem. It's not too hard to replace, after you remove the hood, and get the fan out, from then on, it's easy.

Rod

Alan

This is normal to this failure mode - before complete failure (4 only working) you often get a period of sporadic intermittent correct behaviour (it won't last though).

Running in speed 0/1 will usually cause the final failure to happen faster than if you leave it in speeds 2/3/4...

What fails on the older models is a bimetallic strip heated by the resistors - once it fails it forces full speed by shorting to high speed (4) mode & tends to not ever fully recover - but cool temps may reset it for a while. Later models like yours have a thermal switch that goes OC and turns off all the resistor controlled modes - high speed (4) is direct drive from the switch so still works. 94+ are different again - these tend not to fail - they have no thermal protection device.

Alan

callouie

Thanks, appreciate the insight. I did some reading, and it looks like my skinny arms may make the job somewhat easier.

Bill Ball

Attach a string to the backside of the old resistor pack before you unscrew it, and you won't need your skinny arms to install the new one. Move the string end to the new one and pull it into place.

ColinB

Callouie.
I did it on my RHD car without removing the fan and I think LHD will be the same. You can get skinny arms in through the flexible joint between fan and duct. Wally Plumley has an excellent description of the job. I used Bill's string trick to fit the new one but I think a length of stiff wire would have been even better.

Colin. 89GT

dr bob

I think we used one of those squeeze-finger parts-grabber things, along with the string, to get the part replaced through the rubber boot area. With two of us it took just a few minutes for the replacement.

!!BUT!! Be sure you stuff a few rags down into the area under the outside of the blower duct. I dropped a screw in there and chased that damn thing all over the place with a magnet trying to recover it. Learned my lesson. Also remembered too late that I have a screwdriver that captive-ates small phillips screws.

callouie

Thanks again for the tips. Strangely enough, it's working fine today, but this is on my To Do list for Saturday.