There are a bunch of these in the salvage yards, but look for one that you can return, say in 30 days, if it has problems. I'll be heading to some "Pull-A-Part" yards in Indiana and Kentucky soon. Modules there are less than 50 bucks. I can hunt for one there, but I don't have any way to test them.
You can't make any voltage tests at the module because the connector is up on top. The module unplugs when you pull it down. What you can do is measure on the other end of the wires at the signal switch. This is a really complicated circuit, but there are some things you can try or verify.
First, you need to be able to make the wiper motor run. If you can still do that by pressing the washer button, fine. If not, you can insert a jumper wire in terminal 85 of the "Wiper On" relay under the hood, put the relay back in, and ground that wire. The motor should run on slow speed. When you put the wiper switch in the high position, the motor should speed up. That proves the "High / Low" relay, "Wiper On" relay, and the "high" section of the switch are working. If the motor runs when you press the washer button, it proves the Body Computer's switching circuit is working.
The only thing left is the delay speed sensing circuit. There are two wires between the switch and the computer that you can access by removing the switch. I can't tell from the diagram which wire supplies the voltage and which one is the sensing wire, but what you're looking for is a varying voltage on one of them. One is the black wire with a white stripe. The other is a dark green wire with a red stripe. When you measure the voltages, I believe one wire should have 12 volts, (possibly 5.0 volts). The other wire should have a different voltage depending on the switch setting. In the "Off" position, both wires will have the same voltage. The voltage on the black / white wire will be the same on the "high" and "low" setting.
Anytime the voltages on the two wires are different, the computer detects that as a delay or "on" position. If you find 0 volts on both wires, it is possible one wire is broken, or the voltage is not being supplied by the computer. If you find the same voltage on both wires regardless of switch position, there could still be one broken wire, but more than likely the break is in the circuitry inside the computer.
The last circuit should not be involved, but it is the "park" circuit that keeps the motor running until it gets to the "park" position when the control switch is turned off. That is the dark green / white wire in the motor connector. There should be some voltage on that wire when the wipers are parked. It should have 0 volts whenever the wipers are moved out of the park position.
Tuesday, March 23rd, 2010 AT 10:03 PM