Hi guys,

I know this has been asked heaps before and I have had a good look through the archives...and that provides alot of good info! but my problem seems to be slightly different to other peoples.

I need to get the wipers working to get registration here...Im not too concerned at the moment with getting the vacuum system working (ofcourse Id love to - and I will tackle that after the car is registered).

The wiper door does not work when you turn the wipers on. and it does not work with the override switch either.

However, I have manually opened the wiper door (as described in the manual) and with the overide switch (under the dash) on ...it stays open.

Now my problem is, even with the door open the wipers do not work either in low or high speed.
but when I push in the wiper switch to operate the wiper/washers the wipers work (but the washer doesn't!). :?

Does anyone have any suggestions where I begin to troubleshoot this problem?

I bought an automotive multimeter today incase I need it to troubleshoot electrical problems. but Im confused cause I read the switch is just a ground?


Thanks for your help!

 

I had the same problem, I started withe wiper motor, new switch. soleniod. Then I changed every other part in the system, hoses, blah blah. Ended up the new motor was no good. you could check your wiper door limit switch, also.

 

It helps a great deal to have a schematic with this since there are several controling interlopers.
Also depends on year. The book said 68-70 I suppose after this the motor may be grounded instead of positvedededddedded.

The power is 12 red/white stripe this goes to your door safety switch on the firewall and this feeds the wiper motor-18 red. The other end goes to (dash) wiper dr override switch and back to 12 red the light switch for power- This apparently works since your motor does work. This power also goes through the door safety switch, this is near the vacuum motor on the firewall. It works since you have power.

I believe all other wires to be negative. Its kind of backwards if you see what I mean since the motor has no common ground but a common positive instead.

18 L green, 18 yellow, 18 L blue operate the motor.
18 D blue looks like the washer wire.
I think these if jumpered to ground, the contact blades on the motor harness will operate the motor in speeds and washer function. A test to see if the motor resistances do work, thats where the speeds are.
These are the colors of the wires on each thinger. In&in>out& out.
The wiper switch operates a w/s/w dr relay. 18 LG> 18 B &18 B/W The other half is 18 Y & 18LBL
and a w/s wiper dr override switch.18Y&18LB >18Y & 18 LB
Also a w/s/w dr sol. 12 R/W & 12 R
These are under the dash. One of them is the vacuum wierd thing that is maybe screwing up your door opening.

Switch has 18 LBL, 18LB, 18B, 18 DBL

This is a list of wires to functions. Some of them do many things.
black = low speed? this must be Light green since there isn't a black on the wiring diagram. LG also seems to be ground for other functions such as lights. It runs through out the car.
L blue= high
Yellow = motor feed
Dark blue= windshield washer switch to washer

Wires are labeled in gauge 12, 18 or whatever. Small numbers being larger in diameter. 12 is usually a main feed wire.
Colors are DG= dark green. Bl = blue and so on.
A slash-/ means its striped. B/W= means its a black wire with a white stripe. If you get a schematic it helps to color in the wires to some extent to follow them. A color spot on the end just so you don't get lost.

My guess is the switch is bad or one of those controllers is. Bad might just mean it isn't hooked up well. All this stuff is under the dash. Switch you know. I think the solenoid is under the center console and the relay attached to the instrument cluster or column. You can find them by wires leading.
The solenoid? has vacuum lines too.
You might as well trouble shoot the vacuum system too while under the dash, its part of it. The only other part is the controller on the fender.

 

Thanks for the info Techno....you definitly live up to your nickname!

You have given me a bit to think about...I will have another look tomorrow . Ill let you know how I go.

Im thinking it might be the switch (hoping....). So how do I test whether the switch is bad or good? Im confused with all the 'grounding' stuff :?
Is there a way of testing the wiper without the switch? What terminals of the wiper switch do I earth to test?

Cool!

 

Just tried earthing the contacts that plug into the switch - but they still didn't operate the wipers (it operate the washers)...

so now where do I look for the problem?

Would the Relay (located in under the center console) be the next thing? Is there a way to test whether the relay is working?

 

Ground is just a common negative. It runs everywhere there is metal. Just like the ground outside your house, it runs everywhere.
So instead of running 2 wires to every electrical item only 1 wire is run. Power to a bulb and then the other wire is hooked up to the chassis, ground. Only the wire with power has a switch. On or off.
This motor is odd in that they usually have 1 negative- ground and multiple positives. This one is reversed though. 1 postive and multiple negatives. They probably did this just to confuse people.

This sounds like a really complicated and involved test but its actually really simple when you do it. Your just finding out what the switch is making contact with on the black wire. If the other wires aren't being made contact with in the switch then the switch is bad.


You can test the switch first. Disconnect the harness and test the connections on the switch. In off and the speeds. The schematic isn't like cadilac so doesn't show the actual switching it does. So its just guessing.

This is hard to describe but easy to do. You want to put your meter on the switch only. The harness is disconnected. Pick the first 2 contacts and move the switch through the positions. Write down whether its making contact or not. You can label those connectors with the color wires that connect to them.

The meter needs to be on ohms or on diode check. The diode check has a symbol of a triangle with a bar on one point. When you put both of the meter wires together the diode check will make a noise- this is easier if you have it.
Use either one. The problem with ohm check is your meter may output the same for an open as it will for a closed circuit.
Check the output on ohms by putting both the meter wires together.
This is a closed switch. With them apart this is an open switch. You have to be able to tell the difference on the meter.

All your doing is finding out what the switch is doing. Which wires if any are making contact with the others. Then you can compare this info to the harness colors below.
Think of them like spark plug wires. #1, #2 Only they are colors. #1 spark plug wire goes from #1 spark plug to #1 tower on the distibutor. The distributor is the switch in this case. Your not testing spark plug wires or the spark plugs, just the distributor.
Your trying to find out which tower the rotor is making contact with.
Knowing that will tell you if #1 spark plug would fire or not. if that clarifies If the switch is actually switching to the wiper function or not.

-light blue
-LB which I have no idea what that is, should be light black but that doesn't exist. Just compare to the harness. I think its a typo.
***-black > this is actually the one doing the switching. Black is negative and sending this to the other wires selected. The schematic shows it as the center connector but you can figure that out with the harness connector.
-dark blue This I think is your washer. So far from what you said black and dark blue are the only connection being made in the switch.

Meter leads Red and black don't really matter. The colors don't matter in this test.
If you understand the black wire thing above then just check that to the other wires. Otherwise do the following. wires meaning the connector on the switch, not the actual harness.

Red on 1st contact
Black on 2nd Move the switch to the positions and write down what happens. Then just repeat the different combinations.
Move the Black wire to the 3rd contact on the switch. redo.
Move the Black wire to the 4th if there is one. redo.
Move the Red wire to the 2nd contact. redo
"" Red wire to 3rd contact. redo.

Your trying to check all combinations of the switch connectors. There is only so many so you don't have to repeat the ones you did.

Now there should be a whole lot of connections being made. You can compare the connections, what the switch is doing by looking at the wire connector and putting the info together.
Which colors are being contacted. If not too many then the switch is bad.


It should look like black is making contact with the other wires in differnt switch positions. If it isn't then the switch is probably bad.

If it is then one of the other switches is bad. the relay or solenoid.

 

Wow...I can't say how much I appreciate your help and the indepth information you shared....you explained it really well. Thanks so much

I just tested the switch - with the diode function set on the multimeter (I love my multimeter!).....and there are definitly connections at the switch...so the switch seems to be working fine.

So now I guess its a matter of testing the relay and solenoid...if thats possible.

I saw the relay under the console when I was fixing my neutral safety switch (cause the reverse lights wouldn't light up when I was in reverse)....

Is there a way of testing the relay?
Is it just a matter of applying a voltage across the relay? or seeing if there is a current passing through it when the system is on?

can you open the relay up to see whether the soldered connections have lasted over time?

 

I've read that the 68 is completely different than all other years.

Every article I've read (corvette fever) as well as others stated this in the first paragragh

Techno,

Is the info you gave above for the 68 or some other years. I've got a 68 and have copied your info as you post, When I get back to my car I'd like to pick your brain some.

It would be helpful if the year of the car was listed in the first post so anyone reading this would know if they can help or not.

Rick

 

Good point Rick - I thought I mentioned what year my vette was....I usually do but forgot to this time. :blush:

Its a 1970, 350ci/300hp, Auto.

Have a look at this thread - Wiper System Explanation

Its got an excellent explanation on the wiper system, description of its components, both vacuum and electrical.

and its great for you cause it has an explanation of the 68 system too.

Techno is an awesome dude!

 

The schematics are from a haynes book 68-70.

I read some of that thread and it does say the 68 is different. I didn't comprehend the differences since I'm not working on it.
Most of the stuff is the same except the differences

At this point the schematic sucks.

I don't understand the switch or why its grounding both motor wires.

both the relay and solenoid, which is a relay should click if powered up isolated. The yellow to them is fuse box power, ignition key?
The light blue and light black? are the grounds for both of them, from the switch. It looks like both get activated but both control a motor wire so I can't figure anymore out

You can either supply the relays with power and listen for a click or do this
My best guess here is to make sure the yellow is powered with the ignition on. That takes care of that wire.
The 2 wires from the switch should be getting grounded from the switch. so switch the switch and see if the connection on the relay and the solenoid are grounded. That takes care of the switch and wires to the relay and solenoid. There should be something wrong at that point.

Now on 68 I just checked and there are 3 more wires with a seperate connector to the wiper motor. It looks like these wires are the internal switches. 3 wires run from the motor to the gear box and some of those 3 special connector wires either run to the motor or the gear box area. That article I think describes those.
The 68 has 2 connectors and 6 wires. One connector goes directly on the wiper motor and the other doesn't. I don't have a washer thing so don't have that one showing.

 

Has it always worked like this? I suggest checking the connector on the back of the switch. It sounds like it is plugged in backwards.

 

Ok I have to UPDATE you all - GOOD NEWS!!!!!!!!!!!!!!!!!!!!!!!!!!

Firstly, let me thank you for your time and help on this problem I had with my wipers.

I did research the archives before posting this thread, but the extra in-depth info I got in this thread from you guys really helped.

Thanks for those long in-depth posts Techno. They really helped as you took it right back to the basics, the very basics :o

I read in the archives that the connector to the wiper switch may have been put in back to front, and that someone had the same problem - wipers only operated when washer button pushed in.
So, I tried this, and it didn't work.
and it didn't look like the connector should have been put in backwards because it looked 'right'.
So thats why I thought it must have been something more complicated.

I tested the switch thanks to Techno's help and it was functioning correctly. So I then thought wiper relay (as these relays can become faulty over time) or solenoid.

But after Techno's careful explanation of GROUNDING and THEANDIES mentioning the plug in backwards thing again - I suddenly realised I hadn't grounded the unit when I tested the connector in backwards.


As soon as I realised this I flipped the connector one more time and screwed the unit back into the console (GROUNDING it - which is a very important thing! :blush.............and the RESULTS:

................. IT WORKS PERFECTLY!!!!!!!

I just want to emphasise one more time that if anyone is having the same problem as me - CHECK THIS CONNECTOR first as it looks right when its installed wrong (ie backwards).

In my 70, when the connector is connected properly the two light blue wires are on the passenger side, but I guess wire colours might change depending on year.


Whats next?.....