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#1 |
Registered User
Join Date: Aug 2015
Location: Farmington Hills
Posts: 20
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'87 r10 wiring help
I have a couple of wiring issues on a new to me '87 r10 5.7L tbi.
I have found two loose wires in the engine bay, pictures attached. Tan/white wire appears to come out of the firewall near the steering column. Green wire is near firewall above driver side valve cover. Also, when the headlight switch is on the passenger side blinker indicator in the dash stays on. When the headlight switch isn't on the blinkers/hazards appear to all be working properly. When the headlight switch is on the driver side works fine the passenger side blinks slower and only uses the dimmer of the two filaments. Should I be looking for an issue at the passenger side light, ground perhaps, or does this sound more like something at the headlight switch? Thanks, John |
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#2 |
Registered User
Join Date: Nov 2009
Location: Haines City FL
Posts: 461
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Re: '87 r10 wiring help
Sounds like bad bulb on passenger side.
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#3 |
Registered User
Join Date: Aug 2015
Location: Farmington Hills
Posts: 20
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Re: '87 r10 wiring help
That's what I thought too but I swapped bulbs from side to side and same thing.
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#4 | |
Registered User
Join Date: Apr 2009
Location: Pflugerville, TX
Posts: 594
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Re: '87 r10 wiring help
Quote:
The green wire is a 12v+ signal from the A/C to the ECM to bump up the idle and tell the ECM the A/C is on. |
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#5 |
Registered User
Join Date: Aug 2015
Location: Farmington Hills
Posts: 20
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Re: '87 r10 wiring help
So since I don't have A/C or dual tanks I should be good for the "loose" wires.
Now to figure out the blinker issue. |
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#6 |
Registered User
Join Date: Aug 2015
Location: Farmington Hills
Posts: 20
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Re: '87 r10 wiring help
A little more info. I removed the front marker lights and signal lights on both side. Turning on the head lights like this does not result in the dash indicator lighting.
Replaced all the lights after cleaning the sockets with electronic connection cleaner and no change. I did notice that the passenger side signal light never uses the bright filament only the dim. I suspect a bad ground or short in the bright filament circuit. It seems like everything on that side of the truck is on the marker light circuit, including the dash indicator. Any common short locations in this circuit? Where do the signal lights ground? Thanks |
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#7 | |
Registered User
Join Date: Oct 2015
Location: Ottawa, Ontario, Canada
Posts: 752
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Re: '87 r10 wiring help
Quote:
__________________
![]() Was a 77 454 w/308 gear. Taken out 550 lbs. up front with motor clip change. |
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#8 |
STILL PLAYS WITH TRUX
Join Date: Nov 2002
Location: Melbourne, Fla.
Posts: 2,764
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Have you replaced the flasher unit yet?
You may also want to remove the headlight switch and clean the terminals on the switch and connector with some contact cleaner and see what happens. |
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#9 |
Registered User
Join Date: Aug 2015
Location: Farmington Hills
Posts: 20
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Re: '87 r10 wiring help
Just to close this one out. I found the ground contact inside the turn signal socket, the one that contacts the bulb base, has broken off.
Any suggestions in replacement sockets? Napa has an Echlin unit that looks ok. |
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