TEST 5: High Speed Circuit Resistance Test
IMPORTANT: If you haven't already disabled the air bag system, do so now. You can find the instructions here: Disabling the Air Bag System (SIR).
It's possible to resistance test the High speed wiper switch circuit and in this test section I'll show you how to do it.
The circuits that you'll be resistance testing are the number 3 and number 4 of the gray Multi-Function Switch connector.
NOTE: This test is done with the gray connector disconnected from the instrument panel harness connector.
This is what you'll need to do:
- Disconnect the battery negative (-) terminal.
- Disconnect the gray Multi-Function Switch connector from the instrument panel harness connector.
- Place your multimeter in Ohms mode.
- With the multimeter test leads, probe the wires that correspond to the circuits labeled with the number 3 and number 4 of the gray connector.
- Place the wiper switch in High speed.
- The multimeter should register continuity (0.2 Ohms).
- Select Low speed (or any other speed) on the wiper switch.
- The multimeter should register NO continuity (usually displayed as OL).
- Select and deselect High speed several times.
- Each time High speed is selected, the multimeter should show continuity.
- Each time the wiper switch is taken out of High speed, the multimeter should show NO continuity (OL).
Let's take a look at your test results:
CASE 1: The multimeter registered the indicated continuity. This confirms that the High speed circuit inside the wiper switch is OK.
If your GM pickup, van, SUV or mini-van is experiencing a 'No High Speed Wiper' problem, then you have eliminated the wiper switch as the cause. The most likely cause will be a bad wiper motor.
CASE 2: The multimeter DID NOT register the indicated continuity. Re-check your connections and repeat the test.
If the multimeter still does not show you the indicated continuity when placing the wiper switch in High, then the wiper switch is bad.
Wiper Switch Test Summary
Hopefully this test article save you time and money by either eliminating the wiper switch as bad or by condemning it as being fried and the cause of the Wiper issue on your GM vehicle.
I know that this article is pretty narrow in its focus and doesn't cover all possible malfunctions and so, I invite you to share your own troubleshooting and repair experience with the rest of this web page's readers. This not only improves the article, but will help anyone else with a similar issue or problem. You can use the contact form below.
Feel free to also check out all of the 'how to test' tutorials found here:
If this info saved the day, buy me a beer!
