Another Wiper malfunction question

Pat S · 05-25-2003, 06:20 AM

Just got a 74 911 and have been having fun figuring out how stuff works.

My first project, wipers...

So the wipers were broke when I got it. I assumed switch or motor since the fuse was good.
Well after tearing everything down and benchtesting it all I'm stumped. Here is what I have so far:

Symptom: Nothing happens at all on wiper or wash.

Switch: Cleaned and benchtested, contacts being made, not sure if all are working as designed but it appears that way

Motor: cleaned and bench tested, runs fine when power applied on 2 prongs, nothing on the others, not sure where it should run when power is applied.

Relay: incorrect, horn relay is installed according to the pin #s. I assume if this is a bad thing, it should only impact intermitent selections.

Output: Testing power to the motor here is where I see it (yes the batt is low):
Pos0 (straight out): Red/wh and Blk/purple with 11.5v
Pos1: Blk/purple only with 11.5v
Pos2: Blk/Yellow only with 11.5v
Pos3: Grn with only 11.5v
Never got any power on blue (washer initiated right?)

Any advice?

Thanks,
Pat

Pat S · 05-25-2003, 03:15 PM

Slight update.

My outputs above are incorrect. Didn't look at all them but here is the story on pos2 (low speed).

Pos 2 has power to blk/ylw and red/wht.
When I connect al the wires to the motor except blk/ylw. I can read power on red/wht and blue? so red/wht and blue must be shorted, I'm just not sure if they are shorted on purpose or not.
I still have power on blk/ylw.
As soon as blk/ylw makes contact, I get 0 readings on every terminal including blk/ylw and red/wht. What sense does that make?

If I run power straight from battery to the terminal where blk/ylw is connected it runs fine.

So what am I missing here?
Pat

RoninLB · 05-25-2003, 03:57 PM

Windshield wiper switch

re: Wiper problems analysis..

Pat S · 05-25-2003, 04:51 PM

Thanks Ronin, read both of those before posting, and checked everything they mention.
Any idea what the motor connections should be? Mine are:

- R/W
| Bk/P | G - Bk/Y
- Bl

Pat

RoninLB · 05-25-2003, 07:04 PM

Quote:

Originally posted by Pat S

Thanks Ronin,
Any idea what the motor connections should be? Mine are:
- R/W
| Bk/P | G - Bk/Y
- Bl

understanding what's happening on the diag. needs some patience.. I don't have any history with both machine, and elec... and I never got into the various legs of the branch for entertainment..But I'm getting ready, LOL...........Ron

RoninLB · 05-25-2003, 07:05 PM

RoninLB · 05-25-2003, 07:26 PM

That Blue/White 53e south connection should be on a rotating contact to enable the wipers to stop in the parked position after being turned "off"........Ron

Pat S · 05-25-2003, 07:58 PM

My diagram is slightly different than the image you posted.
According to Haynes Diagram I have for the 74...
It's similar except that the blue goes straight to the motor (not to relay) and red/white also goes to the motor.

In fact there is no relay at all ???? So I wonder what the relay I checked is really for then? Anyway...

At this point I'm assuming I have a corroded connection somewhere. I bypassed the fuse with jumpers and still had no luck, so it looks like I'll be doing some more tracing work in the morning...

Thanks again for the help.

Pat

RoninLB · 05-25-2003, 09:58 PM

[QUOTE]Originally posted by Pat S

"My diagram is slightly different than the image you posted."
--- the dia. should be for mid '70s foreward.. do you have the Intermittent Control?

"except that the blue goes straight to the motor (not to relay) "
--- so you don"t have an Intermitent Control[relay].. and the posted Blue/White wire is really all Blue wire on your diag. which is connected to the "off" rotating contact to park the wipers.

"and red/white also goes to the motor."
--- It looks like the Red/White also goes to the rotating contact inside the housing

"In fact there is no relay at all ???? So I wonder what the relay I checked is really for then? Anyway..."
--- LOL.. maybe it's for the washer pump.. it's gotta be that..

"At this point I'm assuming I have a corroded connection somewhere."
--- the wiper switch is the routine answer to these wild problems.. the interior of the motor housing, and it's rotating contact is another weak area, IMO