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1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks

Headlight Problem and Random Connector Under Dash?

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Old Nov 26, 2015 | 08:02 PM
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Headlight Problem and Random Connector Under Dash?

I have a problem with my headlights on my 93 f150. When I turn them to the low beam position the high beams are on as well as the high beam indicator, in the high beam position the low beams come on and the high beam indicator is still on. In the pulled back high beam flash position they stay on high beam and of course the high beam indicator is on. In low beam the drivers side headlight is a lot dimmer that the passengers side.

Other thing is there are a couple connectors under the dash that aren't plugged in and I don't see anything that goes to them. I have pictures and will upload soon. Thanks!
 
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Old Nov 26, 2015 | 08:04 PM
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Imgur: The most awesome images on the Internet should be all of the photos. Can get more if needed. Also my license plate light was missing. Put a new one in and it's also not working. Could that plug over the hump be the cause?
 
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Old Nov 27, 2015 | 06:55 AM
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From: Easton,Ks
Originally Posted by DaMonsterMonster
Also my license plate light was missing. Put a new one in and it's also not working. Could that plug over the hump be the cause?
Sounds like a bad body ground. There should be a 10GA or larger wire going from the NEG post of the battery to fender. Make sure it has good connections on each end. The large battery NEG cable goes to the engine block. The frame does not have to be grounded in most cases but the license plate light is an exception to this along with the trailer plug at the rear and they use the frame for a ground. The large NEG battery cable should have a clamp half way to the engine and the clamp is bolted to the frame for the frame ground.

The plug under the heater control in your first photo is for the trailer brake controller.
In the second photo is the Warning Chime Module plug.
As for the Drivers side next to coolant reservoir there should not be a M/F plug in this area.
 
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Old Nov 27, 2015 | 06:10 PM
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Yea it looks like a bunch of 3 wire splices. One of the wires is cut in one of them. So bad ground would reverse the high and low beams?
 
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Old Nov 27, 2015 | 07:06 PM
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From: Easton,Ks
Bad grounds do funny things.
 
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Old Nov 28, 2015 | 04:21 PM
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Originally Posted by subford
Bad grounds do funny things.
Very true. ..
 
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Old Nov 29, 2015 | 08:23 PM
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Headlights work normal now. Two outer wires on the plugs were switched. That wiring mess must have been for aftermarket light s a previous owner put in because there is a KC Light switch on the dash. Haven't looked into the license plate light a whole lot yet. Thabks for the help on the plugs! Those worried me a bit. Was kind of hoping they with to the climate controls cause it is stuck on defrost and the blower motor only turns on on high (bearings are going out in it is probably why it won't work in any other mode than high)
 
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