[72nova2]

car was down for new engine and tranny and now i have no wipers i have 3 wires at the switch with 12 volts and have 12 volts to the motor with a ground wire and less than 1/2 volt on the third wire. how do i check the motor and the switch. my guess would be the motor has gone bad but i dont have the cash to be wrong a few times.

also can i run jumper wires to the motor to just make it run to see if it works

also what voltage should i have to the third wire on the motor; power, ground, and what. i would think it's a signal wire but what should the voltage be?

i'd appriciate any help, thanks.

 

[poncho62]

Not sure of the wiring, but the GM wiper motors have the wiper motor controled on the ground side....I think. Make sure that your ground is good.

 

[troy-curt]

The switch has to be grounded where it mounts.

What brand of car?

Troy

 

[docvette]

Wipers

Doc here imp:

The only power will be at the Wiper motor on the yellow wire. It will be "HOT" in run position only through a fuse.

The other Wires are Grounds supplying speed control and washer pump functions from the switch. GM does not switch the power, it wires it fused hot, and switches the ground. The center wiper on the fast/slow/washer switch is actually a hard ground.

The gray or blk/wht wire will be low speed when grounded, The purple or light blue wire will be high speed when grounded, The dark blue will start the washer pump when grounded. The black pigtail is a hard ground for the motor assembly.(See Photo)

Any voltage reading you may have at those terminals is a "loaded" Ground, or a ground wire that reads voltage because it has no ground on it. Else it would read zero.

First look for a blown wiper fuse (you say the yellow has 12 volts on it, so it should be ok.) Then look for switched grounds missing at the wiper motor. Pull all the wires from the wiper motor except the yellow, put a meter on it to ground set for rx1 scale and switch the wiper switch, at each speed, it should read 000 ohms on the corresponding wire.

Doc imp:
Photo:
Typical wiper schematic

 

[ericgantner]

same prob but with a 1960 GM

Would anyone be able to give me any feedback on the wiper motor for a 1960 Chevy Belair. I am having the same problem. I havent check voltage or anything of that sort yet. I was just wondering if anyone could give me a good place to start.

Thanks

 

[docvette]

fuse

Doc hereimp:

A good place to start is the power fuse at the fusebox.

I can't remember If GM switched the Ground or power way back in 1960, but I think it might have been power...Maybe someone here remembers.

The next best shot is go to your local main library and get a copy of the electrical system from the reference desk...Check the schematic and see how it is wired, Switched power, or grounds..Then check with a DMM to see that the wires are good and as per the schematic.

The switch can also be faulty on a vehicle that old , so if it's hooked up right I'd look there next.

Get the schematic and read it first, If you can't figure it out, scan and post it, I'll help you do that.

Doc imp:

Photo: later model GM
Wipers (switched ground typical)

 

[ericgantner]

i looked at the fuses the other day and nothing directly said wipers would it be hooked in with something else?

Also I was considering the fact that it was just the switch itself would it be ok to hook up another switch temp style and test it. If so what kind. I did unplug the on wire going to the switch one wire seemed weird to me but I also couldn't see that well.

I will also make sure to get over to the library. I had no idea they had stuff like that at the library.

Thanks Doc

Eric

 

[docvette]

Switch

Doc here imp:

You could bypass the switch with another, or even just using jumpers on the plug, but you will still need the diagram to identify the wires...

The fuse will be marked WW or wiper and should be on a circuit on it's own..nothing else should be on that line (unless added later by someone else) To be sure check all the fuses, and replace any blown ones!

The local Main library's usually carry those diagrams, or can be able to outsource them for you..The best one's to ask for are The GM factory manuals, not Haynes or Chilton's ... But any will do if they don't have the GM 's The only drawback is their reference material, so you have to copy them there, you can't check them out...bring lot's of copier change!

Doc

 

[ericgantner]

Thanks for the help I will make sure to get to the library and take a lot of change with me.

Doc would you have any suggestions on what could be wrong with my fuel gauge. The guage has power but it always goes all the way up to past Full. I read a couple of other post but they didn't seem to help me much.

I will also be needing to get some sort of Ohm meter. Do you have any recommendations.

Thanks again

Eric

 

[docvette]

Fuel Gauge

Doc hereimp:

The fuel gauge either has a disconnected or broken sender line on it, or the sender is out...or the tank is not grounded.

If the sender line on most gauges goes out the reading will shoot high and stay there.

When you get your Meter, Check your line on the Rx1 ohms scale with a long jumper wire attached at the tank end disconnected from the sender to the point where it attaches at the gauge, It should read 0.00 ohms...any higher, and its probably bad, run a new wire.

While you are at Rat Shack getting your new meter, ...

Get a 50 ohm and 100 ohm 1 watt resistor, This you can put on the sender line at the tank end, sender disconnected, starting with the 50 ohm, and ground the other end of the resistor, It should read around 1/4 to 1/2 tank.

Then the 100 ohm resistor, The gauge should read about 3/4 tank or better. This will "Clear" the system of it being bad..and point the malfunction to the tank sender...or tank ground missing.

Be sure the sender GROUND at the tank (Black wire/Terminal on the sender/fuel inlet on the tank) is grounded good to a frame ground, or else the sender won't work. The fuel sender is a rheostat, that measures the amount of ground through it, by varying the resistance in relationship to the gauge as the float moves up or down. Somewhat like a "Volume Control" on a radio...only it uses ground.

REMEMBER: The tank sits on steel bands with Rubber insulator's between the tank and the bands, and the filler cap is inside of a big Rubber grommet...so the only possible ground would be the fuel lines and not even those if rubber hose is between the tank and a filter or pump...so the HARDWIRE ground is necessary to make it work!

If the gauge works with the resistors, and the tank is properly grounded, and it still dosn't work, the sender is shot, or the float has a hole in it...replace the sender.

ABOUT your meter, The best thing to do is go to your local Rat Shack...

(you've got questions...We've got....Cell phones, Batteries...Dish network...CD players...DVD players...)

Go to their Parts section or (uuugh!!!) ask one of the brilliant sales associates For a good REASONABLE priced DMM (digital multi meter) It should run right around $39.00 ..

Should be able to read ohms, Continuity, Volts, Amps up to 10 amps, micro amps/volts...This should Be all you need for your tool box if your not doing this on a daily basis...and do just about any job automotive related.

Doc imp:

 

[ericgantner]

wow

Now thats a response

I appreciate the help emensly. I will stop at the rat shack as you say. I understand what you are talking about in regard to the sales people there. "We have answeres" Yeah right.

I will make sure to get that meter for sure It seems like something I will need as long as I have an interest in cars which will be a long time.

Thanks for the help.

I will let you know how it all goes with the wipers and the gas gauge.

Eric

 

[Chopper64]

I think Doc is an electrical God...Good work Doc and as always good answers.:thumbup:

 

[455c-10]

would a 1981 chevy c-10 have a "typical" wiper circuit? my wipers do not work at all and i was wondering if there is a relay at all in the system. if any one knows. thank you.

 

[docvette]

Wipers

Doc hereimp:

The 81 Wiper schematic is typical for your vehicle...GM didn't change much over the years...If it works...don't fix it theory...

The only changes would be if you had timed "Intermittent" wipers, or moisture detectors (start automatically when they sense water) and I think there are few out there for 81..

There should be no relay on that system according to the schematic, so I wouldn't go looking for one.

If the wipers are dead (no power to the yel/black wire on the motor with key on) Look for a fuse..

If you have power, then you are missing a ground somewhere from the switch on out...

Ground the purple or Lt Blue wire at the motor, It should run fast...

Ground the Blk/wht or Gray Wire at the motor, it should run slow..

If both work, you are missing the ground at the switch center wiper (movable Contact) or the switch has gone bad...

If neither Work, Then the wiper motor is locked up, or has burnd out.

Doc imp:

I think Doc is an electrical God...Good work Doc and as always good answers.:thumbup:

Doc hereimp:

Chopper,

Thanks man! I do what I can...

I do appreciate your fine praise!

Doc imp:

 

[455c-10]

thanks doc. i appreciate the help i was just wondering because it has been pouring down raining and i didnt want to spend a whole lot of time in the rain becuase the wife makes sure her car is in the garage...oh well thats how it goes. i appreciate the schematic though it will help alot. my wiper motor and fluid motor doesnt work so im sure it is either a ground or the switch. i am an electrician on f-16s so it shouldnt be too hard to find it.

thanks again for the help.

thanks doc. i appreciate the help i was just wondering because it has been pouring down raining and i didnt want to spend a whole lot of time in the rain becuase the wife makes sure her car is in the garage...oh well thats how it goes. i appreciate the schematic though it will help alot. my wiper motor and fluid motor doesnt work so im sure it is either a ground or the switch. i am an electrician on f-16s so it shouldnt be too hard to find it.

thanks again for the help.

 

[docvette]

Avionics

thanks doc. i appreciate the help i was just wondering because it has been pouring down raining and i didnt want to spend a whole lot of time in the rain becuase the wife makes sure her car is in the garage...oh well thats how it goes. i appreciate the schematic though it will help alot. my wiper motor and fluid motor doesnt work so im sure it is either a ground or the switch. i am an electrician on f-16s so it shouldnt be too hard to find it.

thanks again for the help.

Doc here imp:

455c-10,

Avionics or Craft power? I have always had the utmost respect for you guys...You guys could make magic happen in "No Detectable" Space..at all...and y'all must be triple jointed to fit and work in some of the spaces provided by aircraft manufactures...Avionics Bay? more like a small lake...

I Flew Kero burners for the Airline's Flight training Center for about 15 years, Falcon 10's and 20's tridents and the like. Dassult made good trainers for the heavy's ... Some of those pilot candidate's shouldn't be riding a bicycle much less Flying a JET...

We trained Military from other countries by contract to bring in revenue to keep the FTC open....Third worlders that couldn't afford to crash their own equipment...South African MAJORS in their airforce (19 years old...second cousin to the country's leader...nepitisim? you make the call..)

Had one on a check ride...Wouldn't get his eyes out of the panel on a VFR day...asked him...

"Whadda Ya lookin' at?"
" The HSI"...bam...slapped a no peakey on it..It's failed..

2 minutes later ...

"Whadda ya lookin' at?"..
"The VSI"...bam! slapped another no peakey on it...it's failed...

on and on we went...one no peakey at a time... until the panel was completely covered up..except for the clock and the hobbs....I catch him again...

"Wadda Ya lookin' at now?" (as if there was anything left TO look at..)

" the clock..."

"what time is it?"

"Uhhhh...I dunno..."

Time to get this dawg back to the barn....and for you to go home...

I retired from there about 15 to 18 years ago...

and thanks to modern medicine..

Prozac,

Valium,

Bead stringing ..

and electro~shock therapy..

My manservant KARL(who lays out my dinner attire, White coat and 5 point restraint..arms tied in back..)

and his aide HILDY( who sets the level of current on my patented Frank~N~Stien electro ~ Shock therapy machine) ....

My hands no longer shake...loud sounds don't scare me...and the nightmares have almost gone away..

Doc imp: