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'84 Ford F-150 wiper issue


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chuckdupp
User

Mar 4, 2017, 2:10 PM

Post #1 of 14 (2470 views)
  post locked   '84 Ford F-150 wiper issue  

Hey there.

So I bought a truck with out working wipers. Hoping its as easy as installing a new motor. Wanted to check here first though, before buying a motor to see if anyone could help me diagnose the issue.
So when I turn the wiper knob, wipers obviously don't move, there doesn't seem to be any running noise coming from the motor, but there does seem to be a noise coming from inside the side dash where there knob/switch is located. It's kind of a intermittent crackle.
Made of mistake of buying parts before asking questions on my last project. Trying to avoid that this time around.
Has anyone experienced this? I assume if it was a fuse thing there wouldn't be any noise at all. I tried just starting the wipers buy tugging on an arm as the switch on was.
Would you start with replacing the motor?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 4, 2017, 3:07 PM

Post #2 of 14 (2462 views)
  post locked   Re: '84 Ford F-150 wiper issue  

We don't diagnose electrical problems using past experience. We troubleshoot the problem using a wiring diagram and a test light.





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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



nickwarner
Veteran / Moderator
nickwarner profile image

Mar 5, 2017, 2:22 AM

Post #3 of 14 (2421 views)
  post locked   Re: '84 Ford F-150 wiper issue  

HT gave you the right answer and a factory diagram to boot, but there is one dumb trick you can try. Now realize it isn't a foolproof test either. But switch the wipers on high and hold a screwdriver by the shank instead of the handle. Give the rear of the motor housing a couple taps with the handle. If suddenly the wipers move your motor is crap. The brush holders for the motor are in the back housing, and a light rap can jar them enough to work a little bit if you have enough brush left. By no means should it be left be if they start working, it is a confirmation that the motor is pretty shot. Also, it only tests the one scenario of bad brushes (unlike commutator or field coil failure, a wiring issue, switch issue ect.) But if you haven't gone for that 12v test light yet it can be a useful quick test.

Glad to see you have learned that throwing parts is a bad idea. You found the right site to get it diagnosed properly and not waste money on things you do not need. Its a simple truck. I learned how to drive on the same model. Miss that truck now.


chuckdupp
User

Mar 5, 2017, 3:12 PM

Post #4 of 14 (2401 views)
  post locked   Re: '84 Ford F-150 wiper issue  

hey thanks for the advice guys.
givin the motor a tap or two was the first thing i tried. ive now got the harness disconnected and im trying to check the resistance on the motor vs the voltage coming off the harness.
i cant find color codes online that match what im looking at here but im assuming the black with stripe is the ground and the other wires are speeds.
i bought an auto-ranging multimeter(cheap $20 one). so far its reading a big fat 0 on both. i have a feeling im doing something wrong. time to read up on multimeters i guess.

one more weird thing. when i look at fuse positions online, it has a fuse in position 2 for the wipers, theres no fuse in my truck in that position, but according to previous owner they were working. am i gonna foul anything up by putting the appropriate fuse in there?
thanks


(This post was edited by chuckdupp on Mar 5, 2017, 3:12 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 5, 2017, 4:48 PM

Post #5 of 14 (2395 views)
  post locked   Re: '84 Ford F-150 wiper issue  

I just gave you a wiring diagram with color codes on it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 6, 2017, 1:36 AM

Post #6 of 14 (2373 views)
  post locked   Re: '84 Ford F-150 wiper issue  

It's in the diagram you can see "C" should be a rubber mount with a ground strap of some sort. Mounting bolt could be ground but not reach body of this motor or it wouldn't do anything at all,


T



chuckdupp
User

Mar 6, 2017, 6:53 PM

Post #7 of 14 (2361 views)
  post locked   Re: '84 Ford F-150 wiper issue  

Ah, my bad. that is slightly different than what is under the hood but i think its close enough. instead of bk/pk i have just black.
if i go black to white with the multimeter i get around 8v.
if i go black to db/o it jumps around a bit. it seems to hit 4, stay for a sec, drop to 0, then in a few seconds jump back up the 4, drop again, etc.
i might be blind but i really cant find the fuse for the wiper path. and after lots of googling i'm not finding anything that suggest this model of f150 had one. am i missing something? is there another fuse box besides this one?



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 6, 2017, 6:57 PM

Post #8 of 14 (2353 views)
  post locked   Re: '84 Ford F-150 wiper issue  

The diagram states it's powered by the ignition switch, not a fuse.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chuckdupp
User

Mar 6, 2017, 7:28 PM

Post #9 of 14 (2349 views)
  post locked   Re: '84 Ford F-150 wiper issue  

ah yeah i see that now. new to reading wiring diagrams but now i see how that makes sense. thanks.
so i'm getting voltage at the connection. sorry, i didnt have the switch on before. doh!
is it safe to assume that the motor is the issue now?
like i said before, im getting this weird crackling noise from the switch area, but seemingly no noise from the motor.
when i disconnect the motor the crackling stops...


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 6, 2017, 7:32 PM

Post #10 of 14 (2343 views)
  post locked   Re: '84 Ford F-150 wiper issue  

Turn the switch on high. You should see 12v on the Dark blue with orange wire.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chuckdupp
User

Mar 7, 2017, 7:57 PM

Post #11 of 14 (2325 views)
  post locked   Re: '84 Ford F-150 wiper issue  

Alright, so I'm getting a reading of about 10.5v off the db/o wire with switch on high. Wouldn't that be enough to get it movin' if the motors still good? Couldn't get a ohm reading off the motor itself by probing a ground and the tabs on the motor plug.
Thanks for the help.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 7, 2017, 8:01 PM

Post #12 of 14 (2323 views)
  post locked   Re: '84 Ford F-150 wiper issue  

The reason you are only seeing 10.5v is because you are reading it with the motor plugged in and the motor is pulling it down. It appears the motor is bad.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



chuckdupp
User

Mar 9, 2017, 3:00 PM

Post #13 of 14 (2280 views)
  post locked   Re: '84 Ford F-150 wiper issue  

To everyone involved. Thanks. I have working wipers.
Some of those screws are a real pain in the ass.


(This post was edited by chuckdupp on Mar 9, 2017, 3:01 PM)


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 9, 2017, 3:02 PM

Post #14 of 14 (2273 views)
  post locked   Re: '84 Ford F-150 wiper issue  

Glad to hear that.

We can close this now as solved.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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