1993 Blower Motor Trouble shooting
#1
08-26-2012, 12:44 AM
1993 Blower Motor Trouble shooting
Ok, my father in law blower motor isn't working anymore via switch control. However, it he disconnects the power lead on the motor, I would assume, and connects it directly to the battery and the fan comes on. He changed the fuse which was blowen. I'm thinking a relay is bad or something is up with the connector. Is there a procedure to check the 4 pins with a test light and if need be a multi-meter to see if the proper signals are there.
Just for instance, I had an intermittent MAF fault on my Grand National. I found an electric manual and flipped to the page for troubleshooting the MAF sensor. There was a nice flow chart and with a light and multi-meter we found that I had a bad ground wire. I didn't do the best job of fixing the connector and it was intermittently connecting. So I ran a new ground wire to the chassis and problem solved. In order to fix the ground wire the correct way, it would required to put the engine. There wasn't enough room to sort it out without removing the engine and at $79/hr for labor and the additional cost of pulling the motor I didn't want to fix it through the wire harness and just tapped off the ground line and connected it to the chassis and no more problems.
I'm look for the same type of flowchart for the switch and connector on the 3.3L connector and switch. Even if I knew what the wires where on the connector. Power, ground, single to control the motor speed and resisitor network.
Any help would be greatly appreciated.
Thanks,
Charles.
Just for instance, I had an intermittent MAF fault on my Grand National. I found an electric manual and flipped to the page for troubleshooting the MAF sensor. There was a nice flow chart and with a light and multi-meter we found that I had a bad ground wire. I didn't do the best job of fixing the connector and it was intermittently connecting. So I ran a new ground wire to the chassis and problem solved. In order to fix the ground wire the correct way, it would required to put the engine. There wasn't enough room to sort it out without removing the engine and at $79/hr for labor and the additional cost of pulling the motor I didn't want to fix it through the wire harness and just tapped off the ground line and connected it to the chassis and no more problems.
I'm look for the same type of flowchart for the switch and connector on the 3.3L connector and switch. Even if I knew what the wires where on the connector. Power, ground, single to control the motor speed and resisitor network.
Any help would be greatly appreciated.
Thanks,
Charles.
Last edited by ForcedFed_231; 08-26-2012 at 12:49 AM.
#2
08-26-2012, 04:21 AM
Unless the car has Automatic Climate Control, The system usually consists of fused power to the blower switch which then sends power to the blower motor resistor, which is mounted on top of the housing that holds the blower motor. From the resistor power goes to the blower motor. Depending on which speed is selected, the different resistances provide the selected blower speed.
On the relay panel under the hood at the top of the firewall should be a hi speed blower relay. Because of the hi current required to operate the blower motor the hi speed relay contacts provide the hi current required.
If you get none of the slower speeds AND no hi speed the problem has to be in the supply section either to the switch or from the switch to the resistor and the hi speed relay. The next most logical step would be to get access to the blower switch assy and check the switch contacts themselves. Most of the dash panel parts you would need to remove to gain access are snap fit connections. Carefully watch where the panel is secured and gently pull the section away from the dash. The ideal thing to do would be to measure the amperage required to operate the blower system and confirm if excessive current draw exists enough to blow the fuse. That could even be caused by the blower motor itself. Don't try to measure the current draw with a standard multimeter because they will only measure approx. 10 amps and the blower motor requires 20 or more to operate. You will blow the fuse in the multimeter.
With the info provided, hopefully, you will be able to locate and correct the problem.
Some systems also have a blower enable relay which is also mounted on the firewall.
On the relay panel under the hood at the top of the firewall should be a hi speed blower relay. Because of the hi current required to operate the blower motor the hi speed relay contacts provide the hi current required.
If you get none of the slower speeds AND no hi speed the problem has to be in the supply section either to the switch or from the switch to the resistor and the hi speed relay. The next most logical step would be to get access to the blower switch assy and check the switch contacts themselves. Most of the dash panel parts you would need to remove to gain access are snap fit connections. Carefully watch where the panel is secured and gently pull the section away from the dash. The ideal thing to do would be to measure the amperage required to operate the blower system and confirm if excessive current draw exists enough to blow the fuse. That could even be caused by the blower motor itself. Don't try to measure the current draw with a standard multimeter because they will only measure approx. 10 amps and the blower motor requires 20 or more to operate. You will blow the fuse in the multimeter.
With the info provided, hopefully, you will be able to locate and correct the problem.
Some systems also have a blower enable relay which is also mounted on the firewall.
Last edited by hanky; 08-26-2012 at 04:23 AM.
#3
08-26-2012, 10:26 PM
Unless the car has Automatic Climate Control, The system usually consists of fused power to the blower switch which then sends power to the blower motor resistor, which is mounted on top of the housing that holds the blower motor. From the resistor power goes to the blower motor. Depending on which speed is selected, the different resistances provide the selected blower speed.
On the relay panel under the hood at the top of the firewall should be a hi speed blower relay. Because of the hi current required to operate the blower motor the hi speed relay contacts provide the hi current required.
If you get none of the slower speeds AND no hi speed the problem has to be in the supply section either to the switch or from the switch to the resistor and the hi speed relay. The next most logical step would be to get access to the blower switch assy and check the switch contacts themselves. Most of the dash panel parts you would need to remove to gain access are snap fit connections. Carefully watch where the panel is secured and gently pull the section away from the dash. The ideal thing to do would be to measure the amperage required to operate the blower system and confirm if excessive current draw exists enough to blow the fuse. That could even be caused by the blower motor itself. Don't try to measure the current draw with a standard multimeter because they will only measure approx. 10 amps and the blower motor requires 20 or more to operate. You will blow the fuse in the multimeter.
With the info provided, hopefully, you will be able to locate and correct the problem.
Some systems also have a blower enable relay which is also mounted on the firewall.
On the relay panel under the hood at the top of the firewall should be a hi speed blower relay. Because of the hi current required to operate the blower motor the hi speed relay contacts provide the hi current required.
If you get none of the slower speeds AND no hi speed the problem has to be in the supply section either to the switch or from the switch to the resistor and the hi speed relay. The next most logical step would be to get access to the blower switch assy and check the switch contacts themselves. Most of the dash panel parts you would need to remove to gain access are snap fit connections. Carefully watch where the panel is secured and gently pull the section away from the dash. The ideal thing to do would be to measure the amperage required to operate the blower system and confirm if excessive current draw exists enough to blow the fuse. That could even be caused by the blower motor itself. Don't try to measure the current draw with a standard multimeter because they will only measure approx. 10 amps and the blower motor requires 20 or more to operate. You will blow the fuse in the multimeter.
With the info provided, hopefully, you will be able to locate and correct the problem.
Some systems also have a blower enable relay which is also mounted on the firewall.
Thanks,
Charles
#4
08-27-2012, 09:47 PM
Unless the car has Automatic Climate Control, The system usually consists of fused power to the blower switch which then sends power to the blower motor resistor, which is mounted on top of the housing that holds the blower motor. From the resistor power goes to the blower motor. Depending on which speed is selected, the different resistances provide the selected blower speed.
On the relay panel under the hood at the top of the firewall should be a hi speed blower relay. Because of the hi current required to operate the blower motor the hi speed relay contacts provide the hi current required.
If you get none of the slower speeds AND no hi speed the problem has to be in the supply section either to the switch or from the switch to the resistor and the hi speed relay. The next most logical step would be to get access to the blower switch assy and check the switch contacts themselves. Most of the dash panel parts you would need to remove to gain access are snap fit connections. Carefully watch where the panel is secured and gently pull the section away from the dash. The ideal thing to do would be to measure the amperage required to operate the blower system and confirm if excessive current draw exists enough to blow the fuse. That could even be caused by the blower motor itself. Don't try to measure the current draw with a standard multimeter because they will only measure approx. 10 amps and the blower motor requires 20 or more to operate. You will blow the fuse in the multimeter.
With the info provided, hopefully, you will be able to locate and correct the problem.
Some systems also have a blower enable relay which is also mounted on the firewall.
On the relay panel under the hood at the top of the firewall should be a hi speed blower relay. Because of the hi current required to operate the blower motor the hi speed relay contacts provide the hi current required.
If you get none of the slower speeds AND no hi speed the problem has to be in the supply section either to the switch or from the switch to the resistor and the hi speed relay. The next most logical step would be to get access to the blower switch assy and check the switch contacts themselves. Most of the dash panel parts you would need to remove to gain access are snap fit connections. Carefully watch where the panel is secured and gently pull the section away from the dash. The ideal thing to do would be to measure the amperage required to operate the blower system and confirm if excessive current draw exists enough to blow the fuse. That could even be caused by the blower motor itself. Don't try to measure the current draw with a standard multimeter because they will only measure approx. 10 amps and the blower motor requires 20 or more to operate. You will blow the fuse in the multimeter.
With the info provided, hopefully, you will be able to locate and correct the problem.
Some systems also have a blower enable relay which is also mounted on the firewall.
I had my father in law check the new fuse he put in and it was blown already. So there is a short somewhere. Now it will be a matter of tracing through the wiring. A schematic of the wiring would really be helpful.
#5
08-28-2012, 02:20 PM
Until you can locate a wiring diagram check your owner's manual and see if any other systems are served by the same fuse. If so, you may have to temporarily remove each system from the supply to help isolate the defective circuit.
#7
08-29-2012, 03:25 AM
I'm going to have to wait until this weekend to do anything because I'm going out to help my true father in law, he is building a house. I will have more questions and I might post pics with questions. I'm sure we can work through this and figure it. FWIW, I have a degree in electrical engineering. Unfortunately without schematics or diagrams it isn't of much use. I may have access to some information at work. A lot of our techs used to work for GM service shops. They did tell me that they had manuals on top of manuals at home.
#8
08-29-2012, 02:36 PM
Just kidding, but like your being out on a limb without a diagram, so it is without the manuals in spite of how many they have.
Hope you have a good holiday and don't spend it chasing the problem with the blower.
Never fear , someone else isn't going to repair it on you although you probably wouldn't mind, what do you think?
Hope you have a good holiday and don't spend it chasing the problem with the blower.
Never fear , someone else isn't going to repair it on you although you probably wouldn't mind, what do you think?
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