Heater/blower issue

Topic: Heater/blower issue (Read 2149 times) previous topic - next topic

Heater/blower issue

January 23, 2009, 06:15:24 PM

In my 87 20th anny cat the blower only works on the highest setting but not in the other two intermediate speed settings so in other words
low=off
medium=off
high=on

I tried searching but didn't see this issue listed. Anyone have suggestions for me?

If I get this fixed and the cruise control hooked up this weekend it will officially be the best $1000 car ever.:burnout:

Heater/blower issue

Reply #1 – January 23, 2009, 07:03:00 PM

You most likely need a blower resistor. IIRC you'll be able to access it by opening the glove box door, squeezing the tabs in, and dropping the glove box all the way.

Heater/blower issue

Reply #2 – January 23, 2009, 11:02:26 PM

so a search using "blower switch" did not yield the answer?

If the climate control is not the problem, look here.........http://www.foxtbirdcougarforums.com/showthread.php?t=19544&highlight=blower+switch

Heater/blower issue

Reply #3 – January 23, 2009, 11:08:04 PM

Clearly the wrong search terms were used in my feeble attempt to gain knowledge. Thank you both for helpling me out with that so handily.

Heater/blower issue

Reply #4 – January 23, 2009, 11:20:28 PM

just so you know,, and as already stated, lower the glove box and locate the blower resistor.

remove the switch as well as unplug it.

with your meter, read across the little thermal limiter to see if it is open. If so, replace it,,,,,,,, as in duplicate its function as close as logically possible. Tiny wire jumper in place of the thermal limiter might be in order.

One thing that might cause the thermal limter to blow is debris in the squirrel cage of the blower motor. If there is lint, moths, bugs,, ect ect,,, it makes the fan itself heavy which forces additional current draw on the motor.

so,, lower the blower motor ,, clean the fan part,, then install it back.

With your blower resistor now outside the air box, plug up the connector. Jumper across the thermal limiter just for a moment to verify you have all speeds. If so, replace the thermal limter / fuse with a small guage wire if that suits you.

Sometimes malfunctions in the operation of the climate control can also be the problem.

Heater/blower issue

Reply #5 – January 24, 2009, 12:41:24 AM

this is also in my diy link below to also include some tid bits on the EATC/hvac system with wiring diagnostics / diagrams.

Heater/blower issue

Reply #6 – January 24, 2009, 05:20:12 AM

Anybody know how much that blower motor resistor costs for the EATC setup? IIRC, someone else on here had to buy one and it was not cheap...

Heater/blower issue

Reply #7 – January 24, 2009, 12:16:43 PM

i could not come up with the correct value of seach words to find that thread but yea,, i remember that as well.

Heater/blower issue

Reply #8 – January 24, 2009, 02:09:48 PM

the regular one is $35 at auto hole.... i think they both use the same block, but i am usually wrong:hick:

Heater/blower issue

Reply #9 – January 24, 2009, 04:27:47 PM

The thermal limiter fuse is suppose to blow if there is not enough air flow through the blower resisters.

The resister coils get hot and the air carries the heat away from the thermal fuse.

As far as I know the thermal will not blow due to excessive current draw as suggested above.

The thermal fuse is suppose to blow at 120°C (250°F). If you want to try to repair it you may want to get a thermal fuse from Radio Shack.

Heater/blower issue

Reply #10 – January 25, 2009, 12:28:30 AM

I see what you are saying....humm. I was thinking along the the right path (lack of air flow due to dirty fan) but my concept was wrong. purdy cool design now that i understand the thermal fuse needs air flow. Either way though, when the fan is dirty or the motor is just wearing out, it will have the same end result.

Heater/blower issue

Reply #11 – January 25, 2009, 02:19:31 AM

I got it fixed today, five minute fix. Thanks guys.

I also found out my cruise control cable was not just disconnected like I hoped it was, the cable was broken.

Heater/blower issue

Reply #12 – January 25, 2009, 02:22:44 AM

usually the clip at the vac device in the driver fender breaks.. You sure the cable is broke?

a good thread about this resides in my diy link with pics.

Heater/blower issue

Reply #13 – January 26, 2009, 01:07:24 AM

Yep I pulled the thing apart expecting to see the broken clip and to my dismay I found an intact clip with the cable end still in it, about an inch of cable, and nothing else except a frayed end...

I'll move tot he next project and forget the cruise for now.

Next on the list:
Steering rack?
Shocks/struts?
Interior trim reconditioning?

Heater/blower issue

Reply #14 – January 26, 2009, 12:20:14 PM

do yourself a favor and just get new high/low presure lines from napa for the steering rack.

there were two types of racks available and the fittings are a wee bit different.