No voltage at windshield washer pump

[JPaul]

I've done a lot of searching on the subject of windshield washer wiring and haven't seen anything that seems like it fits my circumstances...

My '87 Targa is 6 mos. new to me so I'm working through stuff that's not working. Among items on the list is the windshield washer. This is my daily driver so I'm not at liberty to leave her in the garage when rain comes between garages.

When I first diagnosed the problem, I sure I had an old, dying pump that needed replacement. A voltage check at the pump side indicated 3.6 volts. That was curious but also found the pump was rusty and went ahead and replaced it.

Now I'm checking again and get no voltage at all. I've checked the wire harness plug from the steering stalk and it's secure and without corrosion. I was thinking of doing a resistance check on the steering stalk switch to make certain it was completing a circuit but, I know that when I pull the stalk back it's making the wipers go so I'm assuming the switch is good. Reasonable???

Looking at my copy of Bentleys, I see there's an in-line diode between the switch and the intermittent wiper relay box. I'm suspicious of both that and the relay box but have no justifiable reason, just eliminating the possibilities.

I'd much appreciate any suggestions on next steps.

Thanks!

JP

[spuggy]

Originally Posted by JPaul

My '87 Targa is 6 mos. new to me

And no pictures? That's not gonna fly...

This is my daily driver so I'm not at liberty to leave her in the garage when rain comes between garages.

Kudos for treating the car as transport. I think they prefer to get driven frequently.

It does make it tougher to fix some things - especially if it's your parts-getter that you just spent 3 hours dismantling when you realize you need to buy something.

A voltage check at the pump side indicated 3.6 volts.

Yah. that's more than slightly suspect.

You might want to check the washer hoses and/or nozzles aren't blocked as well, to avoid disappointment when you get the electrics working and still no workee.

Now I'm checking again and get no voltage at all. I've checked the wire harness plug from the steering stalk and it's secure and without corrosion. I was thinking of doing a resistance check on the steering stalk switch to make certain it was completing a circuit but, I know that when I pull the stalk back it's making the wipers go so I'm assuming the switch is good. Reasonable???

I'd say you need to inspect the switch internals. There's a bunch of little reed-type switches in there. It's entirely possible that one or more is stuck, mis-aligned, burnt or otherwise not working but the other sets of contacts are fine. I would guess that the "wash" and the "wipe" set of contacts are different - but I don't know.

You can futz with the electrical portion of the switches, but it's unlikely to do anything to improve the mechanical action if it's really worn. The mechanism being worn out can cause problems in and of itself.

If you still have a voltage drop when you've got the switch working, the harness plug and/or socket can look pretty good and still cause a significant voltage drop. Fine emery paper, a fiberglass "pen" and judicious spreading of the pins works well...

Looking at my copy of Bentleys, I see there's an in-line diode between the switch and the intermittent wiper relay box. I'm suspicious of both that and the relay box but have no justifiable reason, just eliminating the possibilities.

I don't have that diode, but others have described that item (one-year only, IIRC) as non-essential. No reason to remove it if it's working though.

You've got a multimeter, you can check it for correct function easily enough. If it's either open or short circuit, it's toast. If it's low impedance one direction and high the other, it's most likely fine.

As far as the relay goes, clean/spread the pins and socket, and/or swap a "known good" relay in.

[JPaul]

Thanks Spuggy!!!

Promise photos as soon as I get her shined up!!!

Think you're totally on track. Tested the diode, it's fine. Pried the intermittent relay switch apart and found nothing but shiny parts and good solder joints. Emory clothed the contacts so I'd feel like I accomplished something positive.

Back to the obvious. The switch. I'm now going to have fun reassembling the under-the-bonnet works including all the tie wraps I cut. At least I'll know how to get it apart the next time something goes sideways in there.

Will report back when I've gotten switch out and confirmed my ill-conceived notions.

Have a glorious weekend, what weather!!!!

JP

[JPaul]

Okay, having completed my tour of all related components, I was still not getting voltage at the washer pump.

Traced the wiring again and noticed two sets of wires near where the windshield washer pump in mounted. Both having a combination of yellow and brown. Slapped my head and screamed.

I had been monitoring what was obviously the termination for headlight washers (which my car lacks) and wasn't testing the correct leads. They both have perpendicular connectors and I had grabbed the wrong set. Can't believe how much time I wasted tracing this all out. Naturally, as soon as I plugged my multimeter into the correct leads, voltage was witnessed.

Lesson learned. Make certain I'm testing the right circuit.

Thanks for the input Spuggy!!!