71 chevelle, wiper issue

[chrisf]

hey guys, have kind of a strange issue with the 1971 chevelle that i am redoing for a friend. I have power to all the wires going in but no action. i thought the old motor was toast (power in but not turning, thought it was seized) so i replaced it
the arms are off and its just the motor. switch is new as is wiring. motor or washer dont work

any ideas where i could start? thought it was a ground but added a second ground from the battery to the copper ground strap and no luck


one thing i thought was weird is when i turn this thing on and check for power at the plugs all 5 wires have power

anybody have any ideas wher ei could start?

[graluc]

Re: 71 chevelle, wiper issue

Tagging on, got a similar problem on a 72 velle...

[McGuire]

Re: 71 chevelle, wiper issue

Unplug both connectors from the wiper motor. Turn ignition switch to on. There should be battery voltage at the center terminal of the three-wire connector (black wire with yellow trace, usually) and at pin 1 of the two-terminal (washer pump) connector. There should not be any voltage showing at the other pins. If there is you have some wires crossed.

(With the wiper motor plugged in you can indeed see juice at all the terminals, depending on how you are measuring. This simply means the motor is a complete circuit.)


The two outboard terminals on the three-terminal connector go back to the wiper switch to operate the low and high speeds. Plug the connectors back on the wiper motor, turn key on. If you have power at the center terminal, grounding either of these two wires at the connector (you can back probe the connector with a paper clip to ground) should make the motor run. If not, you have a bad motor.

If the motor does run, you have a problem with the wiring or switch. There are four pins on the back of the wiper switch, and you should still be able to make out their markings, 1 through 4. You can test the switch as follows. With the switch in the respective position you should see continuity (~0 ohms) through these respective pins:

Off: 1 and 4
Lo: 1, 2, and 4
Hi: 2 and 4
Wash: 3 and 4

Hope that helps.

Extra note: that you see current at all five wires suggests that there is an open in the harness between the motor and the switch, but maybe not depending on what kind of lamp or meter you are using.

[chrisf]

Re: 71 chevelle, wiper issue

McGuire, AWESOME info!!! i will check it first thing monday morning and see what i can come up with.

thanks for the help its appreciated.

i was getting ready to shoot it.

[ls7gto]

Re: 71 chevelle, wiper issue

dude , i just blew coffee out my nose!
I use detroit speed and engineering wipers on my a body, works great.

[chrisf]

Re: 71 chevelle, wiper issue

ok, did the test like McGuire said and i do know that the motor is working ok.

a bit of history. car is a 71 malibu with a 402. dash was a bar type and he wanted a SS dash. one was located out of a 72 monte and i swapped it in with a new PC board and 71 wiring. i bought a repop wiper switch from year one and looking at the box today it says "for concealed wipers" the other pt# is for non concealed wipers.
i admit i am a stupid dodge guy. i think i may have the wrong switch in there.

would that make sense?

[fabricatordave]

Re: 71 chevelle, wiper issue

it is a slide type switch right???ground the metal part of the switch and see what happens

[McGuire]

Re: 71 chevelle, wiper issue

My memory is kinda fuzzy on this but I think that switch will work but not correctly. (Sounds like Year One can tell you.) Try operating the motor from the switch connector the same way you did at the motor and see if it still works, to isolate the problem as wiring or switch.

I would also take a look at the firewall bulkhead connector -- make sure there are no terminals backed out, fried, or not matched up in their locations.

Some GM cars of around that time (don't remember if this applies to A bodies) have a pair of connectors in the IP harness between the wiper switch and the firewall passthrough -- a three-pin connector and a one-pin connector (the latter goes to the IP ground). One of those could be unplugged or otherwise goofed up.

[greenjunk]

Re: 71 chevelle, wiper issue

did you check to see whether the linkage is in a bind. I think I remember if you hook the linkage bar up upside down it will still fit in the whole but when you flip the switch nothing will happend cause its in a bind. Seems we had a similar problem on our '71, maybe miketblsr has a better recollection, although I am the smarter one so idoubt it ;D

[McGuire]

Re: 71 chevelle, wiper issue

Yep, if you bolt on the bell crank upside down the linkage will be bound up, the motor will not run, and the circuit breaker inside the motor (if equipped) will go open. However, chrisf said he tried the motor with the wiper linkage unhooked, so I think we can rule that out for now.