Jump to content


how to track minor fault??


Recommended Posts

Ok ..so I am not very good with electrical problems .. I am good with mechanical stuff. But I need to fix these little issues myself. I am wondering if anyone would be kind enough to point me in the right direction. I just need some pointers to get started on these little faults. I am just not too sure where to start looking for the problems. I have look at all the obvoius ones like fuse panel, wire conections etc.

Problem 1 My washer pump does not work. It had always leaked anyway so didnt use it, but the pump did work. I have bought a seperate pump that should work fine .. the bottle doesnt leak , I have hooked up the two wires to the new pump (both ways to see if that helped). My first guess is that the switch on the steering column is shot ... how do I test to find the problem?

Problem 2 My rear defroster doesnt work. It is not the fuse. The light on the dash comes on when I flip the switch, but no defrost, How do I test this one .. I have checked the electrical connections at the window.

This is a 77 280 BTW ..Thanks .. Cheers Bruce Ü

Link to comment
Share on other sites

1st get yourself a multimeter, or a test lamp (or even make a test lamp with some wire and a 12volt light globe). That way you can tell if you are getting voltage at the faulty item.

Note: Washer/wiper probably only works when the ignition is switched to on.

Problem 1. : Firslty I'd plug in the old washer bottle/pump and see if it still works. If it does, the switch isnt the problem, its the new washer bottle, or how you have connected it.

To test for power at the washer bottle, connect the test lamp to the wires where the washer pump is (disconnect the pump). Press the washer button in the on the dash. Light should light up.

If there is no light, you'll need a multi meter to test if the switch is working. Do this by switching the mutlimeter to measure resistance.Then plug both ends into the unplugged washer switch. It should read as an open circuit. Then press the button. It should read close to 0 ohms resistance. If it does, then the switch is working. If it still reads as open circuit then thats the problem.

Also you will need a wiring diagram to work out which is the positive feed to the switch. Change the multimeter to measure volts DC 12 volt range should do it, and check if there is a positive feed going to the switch.

As for the defroster, check that you have volatge at the rear window. clip the test lamp to the positive feed and the other to earth, and switch it on and see if the light lights up. You can also measure the resistance across the heater grid on the back screen. once again, open circuit means the heater grid is stuffed.

It might sound stupid but a simple analogy to understaing how electrics work is to think of it like you would think of water in a pipe. (its electrons flowing in a wire, so its not too different).

So for the washer to work power has to flow form the +ve battery terminal to the fuse, then to the dash switch, (which is like a stop valve to use the water analogy). When you press the switch it continues to flow to the pump motor then to ground (-ve terminal). If there are any breaks in the wires, or plug connections have corroded enough to block the flow it wont work.

(The electrons acatually flow from the negative to the positive terminal, but forget that, its not important to know).

You can clean up plug connections with a piece of dry wet & dry paper.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.