Interior blower fan stopped working!
- Thread starter NIGHTMARE
- Start date
turbodog
Donating Member
All the above, plus the relay, plus the dashboard switch are possible causes. Best to investigate carefully before buying parts.
1. check purple wire, as stated.
2. check voltage at motor (at purple wire) if it has voltage (4 - 12 v depending on setting) WITH THE WIRE CONNECTED TO THE MOTOR then replace fan motor.
3. if no voltage at motor on any setting, check fuse.
3a. if no voltage except on high, check resistors
3b. if no voltage only when on 'high' check relay
3c. if no or low voltage at motor when connected, but 12v when purple wire is diconnected from motor, see bottom paragraph.
4. if fuse is OK, check voltage at relay input and output. Re-seat relay and re-test. Probe relay voltage from back of socket with relay in place. If low/no voltage, check dashboard switch.
FWIW: when mine went out, it turned out to be the switch at the dashboard. It was a pain to troubleshoot, because voltages all looked OK with NO LOAD (relay pulled out, probing the contacts in the socket). When I finally tested with relay in place, I found low voltage. The little PCB in the switch was burned. I now have a spare blower motor
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1. check purple wire, as stated.
2. check voltage at motor (at purple wire) if it has voltage (4 - 12 v depending on setting) WITH THE WIRE CONNECTED TO THE MOTOR then replace fan motor.
3. if no voltage at motor on any setting, check fuse.
3a. if no voltage except on high, check resistors
3b. if no voltage only when on 'high' check relay
3c. if no or low voltage at motor when connected, but 12v when purple wire is diconnected from motor, see bottom paragraph.
4. if fuse is OK, check voltage at relay input and output. Re-seat relay and re-test. Probe relay voltage from back of socket with relay in place. If low/no voltage, check dashboard switch.
FWIW: when mine went out, it turned out to be the switch at the dashboard. It was a pain to troubleshoot, because voltages all looked OK with NO LOAD (relay pulled out, probing the contacts in the socket). When I finally tested with relay in place, I found low voltage. The little PCB in the switch was burned. I now have a spare blower motor
.Ok here's the deal. I've got 0 voltage at the purple wire on any setting with it connected. I also have 0 voltage at any setting when its disconnected. I checked the 25amp fuse under the dash marked HTR/AC and its fine also.
Then I disconnected the relay and jumped from the red wire to the purple directly. The fan worked but I had no control over it. It was on high no matter what I had the inside setting.
Sound like the relay?
Then I disconnected the relay and jumped from the red wire to the purple directly. The fan worked but I had no control over it. It was on high no matter what I had the inside setting.
Sound like the relay?
turbodog
Donating Member
Maybe, but not for certain yet. The relay disconnects the resistor pack (through the 'normally closed' contacts, dark blue wire) from the motor and connects it to battery 12v (via the 'normally open' contacts, red wire) when you select 'high fan' (12v on the orange wire). For you to have NO voltage, when selecting ANY speed, would means neither the 'normally open' OR 'normally closed' relay contacts are working. This is unlikely, but not impossible.
When you jumpered across the relay contacts, I'm guessing you went from the red wire (battery) to purple (blower). This did not determine if you have the right voltage coming from the dash panel switch to activate the relay. You need to find out if you are getting 12v at the orange wire (switch on 'high') and 4 - 9 volts (switch on low-med) at the dark blue wire. You need to do this with the relay in the socket and the purple wire connected to the motor (this is exactly the point where I screwed up in my first round of troubleshooting). If you don't have a meter, just get a $2 test light and check the orange wire with it (fan switch on 'high'). If it lites up, replace the relay.
When you jumpered across the relay contacts, I'm guessing you went from the red wire (battery) to purple (blower). This did not determine if you have the right voltage coming from the dash panel switch to activate the relay. You need to find out if you are getting 12v at the orange wire (switch on 'high') and 4 - 9 volts (switch on low-med) at the dark blue wire. You need to do this with the relay in the socket and the purple wire connected to the motor (this is exactly the point where I screwed up in my first round of troubleshooting). If you don't have a meter, just get a $2 test light and check the orange wire with it (fan switch on 'high'). If it lites up, replace the relay.
ok, cause it was only 5$ I went out and bought a new relay. As it turns out this was not the problem.
I'm gonna go check and see what kinda voltage I have at the relay now. Oh, I did have 2 heater cores go bad. That help with anything? Are the resistors in the dash where they could get damaged?
I'm gonna go check and see what kinda voltage I have at the relay now. Oh, I did have 2 heater cores go bad. That help with anything? Are the resistors in the dash where they could get damaged?
turbodog
Donating Member
I don't think heater core failures are related to switch failure (if that turns out to be the problem). I have had the switch fail on 2 s-trucks and an Astro Van (same basic switch). The switch is a bad design. In the Astro, it got so hot it melted the plastic connector on the wiring harness. I had to replace the switch AND splice a new connector onto the harness.
turbodog said:
Interesting. Now I recall it working sometimes then cutting out. I would slide the settings from MAX AC/ up to defrost and it would kick bakc on.
I've had that panel out before. I remember its really not that difficult. Where can I buy new controls? Any chance have a part number for what I need?
I totally appreciate your help!!
turbodog
Donating Member
GM part number is 16032480. Goes for $13.59 at:
http://www.trademotion.com/partloca...catalogid=1&year=1992&make=11&model=S15 jimmy
BWD Part # BL1, $9.49 at O'Reilly's.
Autozone doesn't carry one for our trucks.
Glad I can help.
http://www.trademotion.com/partloca...catalogid=1&year=1992&make=11&model=S15 jimmy
BWD Part # BL1, $9.49 at O'Reilly's.
Autozone doesn't carry one for our trucks.
Glad I can help.
akty
New member
I had a similar problem with my blower motor as well. I changed out the switch in the dash and seemed to work fine for a while then stopped again. It would occasionaly work in certain positions then stop again.
I eventually took out the switch and added a small drop of solder to the contacts and haven't had a problem since. I believe it is a design flaw with the switch when connected to the harness. Not making good contact.
I eventually took out the switch and added a small drop of solder to the contacts and haven't had a problem since. I believe it is a design flaw with the switch when connected to the harness. Not making good contact.
