Testing to see if the wiper switch is BAD or not is not that hard to do. In this article, I'll show you how to do it with a multimeter.
As you are probably already aware of... the wiper switch is part of the turn signal switch assembly (the whole thing is known a Multi-Function Switch) and this bad boy is not cheap!
You an expect to pay around $150+ US for it... so being able to test it and make sure that the wiper switch is truly fried will save you the frustration of replacing something that not only won't solve the problem... but just made you throw your hard earned money away.
OK, to help you navigate this article, here are its main points:
The wiper switch function within the Multi-Function Switch usually doesn't go BAD. Doesn't mean it doesn't happen, because it does and when it does you'll see one of the following symptoms:
The most common culprit of NO Wipers is usually a BAD wiper motor... but not always. So, the focus of this article is to help you test and either eliminate the wiper switch or condemn it as BAD.
As mentioned at the beginning of the article... since the Multi-Function Switch the wiper switch is a part of is so darn expensive, it's best to test it first before buying it. This article will help you to accomplish this.
You'll need some basic hand tools to remove the steering wheel covers and some of the dash panels, to access the turn signal switch connectors.
You'll also need:
As you can see from the list above, it's nothing that's gonna' break the bank.
The Multi-Function Switch, that the wiper switch is a part of, has two connectors.
One connector is a Gray one and the other is Black.
Depending on whether your particular GM pickup, van, mini-van, or SUV has cruise control or not... you'll have a total of about 20+ wires connecting between the Multi-Function Switch and its two connectors.
Don't worry, we don't need to test all of the wires to check the wiper switch function within the Multi-Function Switch. As a matter of fact, we only need to worry about testing a total of 3 wires. These 3 circuits (wires) belong to the Gray connector.
Now, we're gonna' need to identify the circuits (wires) that we need to test... so, let me tell you that each of the Multi-Function switch's connectors has numbers embossed on them to aid you in identifying the circuits:
If you take a look at photos 2 and 3 (in the image viewer above) you'll see these embossed numbers on the connectors.
We are only gonna' concern ourselves with 3 circuits (wires) of the Gray connector and these circuits are:
You'll notice that there's no mention of the colors of the wires... and this is intentional, since the colors on your specific vehicle may be different.
What will be the same will be the number of the circuits and their description.
IMPORTANT: You will to disconnect the Multi-Function switch's connectors from the instrument panel harness connector to identify the circuits to test... and this will require that you disable the air bag system on your GM vehicle (know as SIR: Supplemental Inflatable Restraint System).
Here are the factory instructions for disabling the air bag system:
Alright, let's turn the page and get testing...
“The secret to success is to go from mistake to mistake without losing your enthusiasm.”