TEST 2: Using A Jumper Wire To Bypass The Blower Switch
If you've reached this point, you have confirmed that the blower switch is good. Either because it tested good (TEST 1) or you have already replaced it.
Therefore, the tests in this section are designed not to test the switch itself, but to let you know if there's a problem with the wiring or the components (e.g. blower resistor and blower relay) between the blower switch connector and the blower motor.
Before you start these tests, you first have to make sure that the blower motor is OK. To test the blower motor, this tutorial will show you how: How To Test The A/C-Heater Blower Motor (GM 2.2L).
IMPORTANT: The jumper wire you use must be of a small enough diameter (gauge) so that the blower motor switch connector's female metal terminals aren't damaged. If you use a too thick jumper wire, you may permanently open these terminals up and create an intermittent open-circuit problem.
Alright, these are the test steps:
- 1
Disconnect the blower motor switch from its harness connector and turn the key to the on position (but no need to start the engine).
NOTE: All of the tests in this section are done on the blower switch's harness connector and not on the switch itself. The illustrations in the image viewer show the front view of the female metal terminals of the connector (see image 4 of 5). - 2
Jumper terminals E and C together. This is the circuit that controls blower speed M1. See image 1 of 5.
The correct test result is for the blower motor to run on M1 speed.
IMPORTANT: The vent position lever must NOT BE in the OFF position for this and the other tests in this test section (see image 5 of 5). If you leave the lever in the OFF position, the E terminal (of the blower switch connector) will not get power and this test (and the others) won't work.
- 3
Jumper terminals E and D together. This is the circuit that controls blower speed M2. See image 2 of 5.
The correct test result is for the blower motor to run on M2 speed. - 4
Jumper terminals E and B together. This is the circuit that controls blower speed HI. See image 3 of 5.
The correct test result is for the blower motor to run on HI speed.
Let's take a look at what your test results mean:
CASE 1: The blower motor DID NOT run when two or all of the indicated terminals were jumpered. This tells you that that specific circuit is bad.
Although it's beyond the scope of this tutorial to test these circuits, you have eliminated the blower switch (on the A/C-Heater control panel) as bad. There's a good chance that you've got a bad blower motor resistor. The blower motor resistor can be tested and you can find the tutorial here:
CASE 2: The blower motor ran when all of the indicated terminals were jumpered together. This tells you several important things:
- That the circuits between the resistor connector and the blower motor are OK.
- That the blower motor relay is OK.
No further testing is required of the blower resistor, the blower relay or the blower motor.
Where To Buy The Blower Switch And Save
You don't have to buy the whole A/C-Heater Control Panel to replace the blower control switch since the switch is removable. You can find the blower switch just about in anywhere. The best place to buy it, to save a few bucks, is online.
The following links will help you comparison shop for the blower motor control switch:
More GM 2.2L Diagnostic Tutorials
I've written several more tutorials that may be of interest to you that you can find at: GM 2.2L Index Of Articles.
Here's a small sample of the tutorials you'll find in the index:
- How To Diagnose Misfire Codes (GM 2.2L).
- How To Do A Fuel Injector Resistance Test (GM 2.2L).
- Troubleshooting A Blown Head Gasket (GM 2.0L, 2.2L, 2.5L).
- How To Do An Engine Compression Test (GM 2.0L, 2.2L, 2.5L).
- How To Test The GM 2.2L Ignition Coil Pack (at: easyautodiagnostics.com).
If this info saved the day, buy me a beer!
