Oldsmobile fan blower troubleshooting help

LLEWEY

MEMBER
1993 OLDSMOBILE 98
6 CYL
2WD
AUTOMATIC

Ok, I have a 1993 Olds 98 and it started out with a fan blower problem. I checked all fuses, and all connections to the blower. All were good. So, I bought a new blower motor, (thinkig that this would be it) NOPE! I have been looking on the internet for help for three days and couldnt really find any real answers on how to solve this problem. If anyone could go through a step by step process to help that would be great! I'm mechanically inclined but, I've never worked on an Oldsmobile before. I have no book either so, location of said things to check would be of great help.

Thanks for any and all help.

1 Reply

KHLOW2008

MECHANIC
41,815 POSTS

First we have to determine if it is power supply or grounding circuit that is causing the problem.

Is system Automatic or manual HVAC and does it have dual climate control?

BLOWER MOTOR TEST

1. Unplug blower motor electrical connector. Turn ignition on. Press DEF (defrost) button. Set blower motor on high speed. Measure voltage between blower motor harness connector Purple wire and ground. If battery voltage exists, go to next step. If battery voltage does not
exist, check Purple wire for open or short to ground.

2. Measure voltage between blower motor harness connector Purple and Black wires. If battery voltage exists but motor does not run, replace motor. If battery voltage does not exist, check Black (ground) wire for open circuit.

BLOWER CONTROL MODULE TEST

1. Unplug electrical connectors at blower control module, located in blower housing. See Fig. 14. Turn ignition on. Press DEF (defrost) button. Adjust blower motor speed to high.

2. Measure voltage between 2-pin connector terminal "B" (Red wire) and ground. If battery voltage exists, go to next step. If battery voltage does not exist, check Red wire for open circuit.

3. Measure voltage between 2-pin connector terminal "B" (Red wire) and 4-pin connector terminal "C" (Black wire). If battery voltage exists, go to next step. If battery voltage does not exist, check Black wire for open circuit.

4. Measure voltage between 4-pin connector terminal "B" (Gray/Black wire) and ground. See Fig. 15. If voltage is not about 8 volts, check Gray/Black wire for open or short circuit. If wire is okay, temporarily substitute known good programmer. Retest system. If voltage is about 8 volts, but blower motor does not run, check blower motor and Purple and Black wires for short or open circuit. See BLOWER MOTOR TEST under TESTING. If blower motor and wiring are okay, replace blower control module.

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