blower motor only works on hi. (fixed it)

[E-Rue]

i thought for sure it was the 4 position switch, so i swaped it with the one in the sy. didn't help. you guys have any ideas where to look next?

e

 

[JSM]

Not 100% sure on ty, but on MOST GM cars, there is a resistor that sits inside heater box. High doesn't use it, other speeds use varies parts for the diff. speeds.

Probably 3 wires going into it. Maybe it got unplugged, or resistor is bad.

Again, not 100% sure ty's have it but I am guessing they have atleast a version of it.

 

[jwaller]

try swapping the relay that mouted to the heater box..if thats not it then its the resistor like jeff said....most problems I've seen can be traced to the relay.

 

[phoon684]

let me know if you get it fixed i'm having the same problem.

 

[E-Rue]

cool im on a mission!

e

 

[myclone]

Not 100% sure on ty, but on MOST GM cars, there is a resistor that sits inside heater box. High doesn't use it, other speeds use varies parts for the diff. speeds.

Probably 3 wires going into it. Maybe it got unplugged, or resistor is bad.

Again, not 100% sure ty's have it but I am guessing they have atleast a version of it.

Ditto..

 

[Tommyquest]

it's prolly the resistor on the heater box. I just did mine last month only my problem was 1-2-3 worked and 4 didn't. New resistor cured that. $10-$12

 

[Opie]

Everytime I've had this problem, it's been the relay.

 

[Loeryder]

Blower motor control relay.

Its the big shiny one right on the blower motor box.
It actually has resistors in it that step down the voltage for each speed.
On HI the resistors are all bypassed and 100% voltage goes to the motor, thus why it works on high only and not any other speed.

HTHs

 

[warmpancakes]

the resistors arte actually mounted inside the heater box (for cooling purposes) they can be accessed from the outside as they just stick through a hole in the box.

 

[E-Rue]

just so everyone knows.

if you lose everything but high on the controls, its definately the relay mounted ono the outside of the fan box under the hood. swaped it out tonight. only took about 5 minutes.

e

 

[phoon684]

cool i will try that and see what happens.

 

[syclonekid43]

1-2-3 are running off the relay. 4 is direct power to the blower motor all the time. i see that you fixed the problem. i was going to say on my truck i checked the both of them and it was notthe problem.if this is not the case for the people this happens to next. there is a chance that the switch on the heater control panel inside the truck goes bad. this happened to my truck the switch inside burned up onme and i lost all but high on the blower motor.

 

[lavaman]

FWIW, the Blower Motor Resistor is an AC Delco Part. GM# is 00526897.

 

[V6 Kompressor]

Ok, just for my 2 cents in, all the blower speeds go through the relay, just the first 3 speeds go through the normaly closed contact of the relay and the high speed goes through the normally open contact of the relay. When you select high speed, the relay actuates, bypassing the resistors located in the heater/ac housing, and connecting the blower to a circuit that goes to a fuse link, connected to the battery, thus taking the big current draw off of the switch in the dash. The switch in the dash will go out occasionally, burning up the contact and sometimes taking the connector out with it, also. usually when this happens, you have nothing but high speed or no speeds. The new relay I got from napa, had a diode internally installed backwards, so that everytime I put the switch in high speed, it would blow the 25 amp a/c heater fuse. Make sure you mount the relay back just like it came off, cause if you install it upside down, water will eventually fill it up and cause problems also... Steve.