The jerks at Big-O won't pass my car since the stupid windshield washer doesn't work.

I found the problem, but can't figure why it's happening. I get around 9-10 volts at the positive wire on the pump when it's not plugged to the pump. When I plug it in, it drops to .20 volts. What's causing this?

Sounds like a short to me.

pump probably shorted out. get a new pump and that will solve it. or cut the line and wire in a inline waqsher pump. I did it in my first 84 2m4 and it worked fine pulling fluid through the dead pump on the resivoir.

If a short pulled that voltage that far down with 10A at the source you'd have some melted wiring. I think you have a bad connection causing the voltage to not match the source and when you run it, it empties out the tube (water flow analogy). To test the pump motor, hook-up some jumper cables and source from that. Just touch the wire to the hot side as you still may have a shorted pump motor. As for the source, check it on the hot side of the fuse and work your way in either direction depending on the voltage reading there at the hot side. If it is low, then you need to work backward from there (toward the battery). If it is close to the voltage at the battery, then work your way forward (toward the pump). Let us know how you make out as these cars are starting to get old and you won't be the last to have this problem. GL!

P.S. I have an '87 manual so let me know if yo want me to post any schmatics for you.

P.S.S. I have never heard of inspection failure for a washer pump in my 45 yrs... They're getting tough

[This message has been edited by 87GTZ34 (edited 09-28-2006).]

Here's the thing. I have 3 good used pumps and a brand new pump. These all work in my other Fiero and when I put them on the car battery charger (2 amp). I get full voltage at the plug if it's not plugged to the pump, but as soon as I plug it in, it drops from 10 volts to .20. I even ran a seperate ground.

I've tracked the pink wire through the firewall, but it disappears into black tape and can't find where it starts. There's nothing on the fuse panel for the pump and nothing mentioned in the Haynes or Chilton's for the panel. So I assume it comes from the column? Any idea where it starts? I'll put in a whole new wire and try that, but I need to know what wire it is.

Thanks.

SCCA Let me get my kids fed and then I will look in my manual for the schematic. So you've verified the pump motors work so you're not getting enough current through the circuit. When I get back, I will post what circuit it is on. Sometimes this is a result from a faulty fuse. It conducts but barely. It can't flow enough to get to the source voltage so when you tr to "sink" current into a device... it chokes. Do give me 30 min and I'll post back. If you haven't changed all of those 20 year old fuses you may want to consider it. I have 2 '87 GTs and that was the very 1st thing I did when I got them. Back in a bit.

I bet it's a bad diode on the wiper control board. A diagram is here.

[This message has been edited by spark1 (edited 09-28-2006).]

you have a high resistance connection, or the switch is bad. (voltage drop under load is a sign of high resistance or under sized wiring, just for ref. a shorted motor would blow the fuse.)

here is the circuit, click for full size:

[This message has been edited by tjm4fun (edited 09-28-2006).]

quote Originally posted by tjm4fun: ...just for ref. a shorted motor would blow the fuse....

not always true. the 84 I am used as an example had a bad pump that was shorted. a voltmeter on it showed 6 ohms. I cut the wires and hose spliced in a aftermarket pump and away it went.


His problem is obviousally not a bad pump cince he has a handful of known good pumps thouigh, so my point is moot. but a shorted motor does not always mean blown fuses. they can short at places in the winding that will simply turn them into heaters or humming electrical devices but not draw enough current to blow the fuse.

you're right! for some reason I was thinking that the wiper/washer was on a 10 amp or so, it shows 25 in that diagram. it would likely vaporize the windings in that little motor.!
I should put my glasses on when scanning these diagrams.

SCCA is your wiper motor running when run the washer? Also at the wiper motor module take a voltage reading of the grey wire and then the orange wire while activating the washer from the switch. Also the wiper fuse is a 25A in position 16 which is the left most fuse on the bottom row. There should only be two fuses on the bottom row (16 & 17). Let us know what you get for readings on those two wires.


As far as the diode theory goes if only the diode pops the result should be that the wipers would have to be manually parked w/ the switch. The diode is used for a feedback manual switch that feeds an elect***ic switch and the diode restricts the current from feeding back into the manual or wiper switch side of the elect***ic switch. However, if someone told you the diode blew and it was actually the elect***ic portion of the park mechanism I could believe that. I don't have visibility into the elect***ic portion of the park switch so that is only an educated guess looking at the schematic.

[This message has been edited by 87GTZ34 (edited 09-28-2006).]

Here's a simplified drawing showing why I think the diode on the wiper control board is bad.

Notice how 360 Ohms is enough to prevent pump motor operation and that current to the washer pump must go through the diode?

Of course the wash switch or park switch contacts may also be bad but that's unlikely.

well, first thing, is does he have intermittent wiper option? or is this the straight wiper system? if it's the non variable pulse, then the diagram I posted is ok to go by. if it's the intermittent type, then there is more too it.
good catch.
Actually, according to the diagram I have, that simplified diagram you made is close, but mine shows that diode and resistors you list in the column switch, not the wiper pcb. that is clear, the page I took the pic of with how to test the wiper board is too blurry to read, at least the washer part. that's too bad, I have to make a list of the pages with bad pics and redo them this winter when I have some time to sit in the library all day.
The chart for washer not working calls either the washer motor or the wiper board as the only failing parts, doesn;t even mention the column switch failing. but those charts are not known as great aids to fixing anything except the dealers bottom line!

likely its the wiper motor.
there is a switch on the motor, which lets the squirty circuit know when its OK to squirt. the switch is bad/dirty.
if you have intermittant wipers, and the delay is not working - this indicates a bad controller in the wiper motor.
you can get Rodney's kit, or get a new board in the "Help!" section of most parts stores. GM used this setup in MANY cars, and they are all failing. so parts be bountiful.

the motor itself is pretty easy to get in & out. hardest part is connecting/disconnecting the arm. other than that, its 3 bolts & a connector.

I tracked the pink wire through the firewall and put my voltmeter on it on the inside of the car. It reads the same voltage in the cabin as it does at the washer pump. So it's losing the current before the wiper motor? The only thing I can think of is it's got a bad wire/connection at the stalk?

actually the wiring diagram shows that the line comes out of the wiper motor, goes back thru a bulkhead connector and back out to the wiper motor. it is very strange and incomplete diagram, or I missed the full page.

I'd say it's a bad connection somewhere, I just went through that with my MIG welder where the solenoid for the shielding gas would not open eventhough the the plug terminals showed proper voltage, further up stream I found that the terminals coming out of the power source had corrosion and removed and cleaned them and that solved the problem. A test light would have helped reveal the erroneous voltage reading quicker than my multimeter because it wouldn't have lit up under that circumstance.

quote Originally posted by tjm4fun: actually the wiring diagram shows that the line comes out of the wiper motor, goes back thru a bulkhead connector and back out to the wiper motor. it is very strange and incomplete diagram, or I missed the full page.

Actually it does just that. The pink wire from the washer goes through the bulkhead to the column switch connector that has a pink jumper from pin B to F, then goes back through the bulk head on the orange wire that connects to the wiper motor connector pin 2. Here's what the connector at the base of the steering column looks like:



edit: If you pull the connector off the wiper motor and measure resistance from harness pin 2 (orange wire) to ground, you will see the washer motor resistance of about 100 Ohms. Put 12 Volts on the orange wire (jump pin 1 to 2 with the ignition on) and the pump should run.

[This message has been edited by spark1 (edited 09-29-2006).]

I should have looked at my wiring pics closer. this is the pulse wiper wiring, very clear. Iwas looking at the pulse troubleshooting pages that came out blurry.
maybe this will help:

quote Originally posted by 87GTZ34: SCCA is your wiper motor running when run the washer is activated? Also at the wiper motor module take a voltage reading of the grey wire and then the orange wire while activating the washer from the switch. Also the wiper fuse is a 25A in position 16 which is the left most fuse on the bottom row. There should only be two fuses on the bottom row (16 & 17). Let us know what you get for readings on those two wires. As far as the diode theory goes if only the diode pops the result should be that the wipers would have to be manually parked w/ the switch. The diode is used for a feedback manual switch that feeds an electronic switch and the diode restricts the current from feeding back into the manual or wiper switch side of the electronic switch. However, if someone told you the diode blew and it was actually the electronic portion of the park mechanism I could believe that. I don't have visibility into the electronic portion of the park switch so that is only an educated guess looking at the schematic.

Reformatting my diagnostic questions...

0) Did you verify the wiper fuse is good?
1) When you run the washer, does the wiper motor run?
2) What is the voltage reading of the white wire coming out of the fuse box? This is wiper fuse circuit to switch.
3) What is the voltage of the grey wire (wiper module) when activating the washer?
4) What is the voltage of the orange wire (wiper module) when activating the washer?

The complete answers to these questions will correctly direct the diagnosis and save time.

quote Originally posted by spark1: Put 12 Volts on the orange wire (jump pin 1 to 2 with the ignition on) and the pump should run.

Bingo!

But I changed the board with the same version (Rev. 1, also have a Rev.3) and it still does the same thing. This board was taken from my other Fiero with a working pump.

[This message has been edited by SCCA FIERO (edited 09-30-2006).]

quote Originally posted by 87GTZ34: Reformatting my diagnostic questions... 0) Did you verify the wiper fuse is good? 1) When you run the washer, does the wiper motor run? 2) What is the voltage reading of the white wire coming out of the fuse box? This is wiper fuse circuit to switch. 3) What is the voltage of the grey wire (wiper module) when activating the washer? 4) What is the voltage of the orange wire (wiper module) when activating the washer? The complete answers to these questions will correctly direct the diagnosis and save time.

0 - Wiper fues is good and is a 25 amp.
1 - When I try to use the washer, the wipers run.
2 - 11.83
3 - 11.58
4 - 0.20 <--- not good?

Glad you gotter done! Still, I've never heard of the inspection station checking the washer though. Here in Florida they abolished inspections... So of course now everybody drives with bald tires and no brakes but not to worry - the insurance companies will just keep raising rates until only the affluent can afford it.

Hey SCCA FIERO, what do you mean when you say you dummied up another wiper motor??

Steve

Basically I just held it by hand close enough to plug it into the harness. The case needs to be grounded (it's grounded when it's bolted in). I just wanted to see if that was the problem without going through all the trouble. It's not too easy replacing the wiper motor. Not sure why the wiper motor would cause the washer pump to not work, but it did.

Anyway, the car is legal for another year and I will never go to Big O again. Last year they said the wiper blades were a little dry and failed them. I went home and cleaned them up and they passed them. I should known then to not go back. But I would have fixed the washer pump reguardless.

quote Originally posted by SCCA FIERO: Not sure why the wiper motor would cause the washer pump to not work, but it did.

The electronics are in the same housing as the wiper motor. It has the pulse/speed/wash control unit specifically that is what your issue was.