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Old 10-11-2012, 02:11 PM   #1

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My 1999 tj headlights go on and off while driving why?

my 1999 tj headlights while driving go on and off i looked at the headlight switch and found that the connector was melted so i replaced the headlight cluster switch and they still go off and on what could it be?

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Old 10-11-2012, 04:37 PM   #2
Knows a couple things...

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If the connector has melted, I'd have to suspect some melted wiring too. Aftermarket headlights?

When you have a choice, buy American.

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Old 10-11-2012, 11:29 PM   #3
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Inside the headlight switch is a small thermal cuttoff switch. It is basically a piece of steel that deforms when heated, and when it does, it breaks the circuit until it cools back down and re makes contact. Any time you have a connector (or in this case, the thermal switch) that does not make good contact, it will heat up. The result is melted wires and connectors. After removing the headlight switch, you can gently pry off the cover to the switch and reveal all the contacts. If you place the switch in front of you, connector side facing away from you and the rocker facing you, you can lift the rocker off and see the thermal switch. Take a very high grit sand paper (600 works best) and gently lift the thermal wire and sand both contacts. On the left side of the thermal wire is a small tab that you can lift carefully with a small screw driver to put a little bit more tension on the thermal wire. A small note, this thermal wire is only designed to carry the current of the headlights only. If you have fog lights wired into the headlight switch it will overload this switch and you will continue to have problems, so, make sure your fog lights are wired to a relay and not directly to the switch. I hope this helps.
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Old 10-11-2012, 11:36 PM   #4
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Mine did this for a while, i just replaced the switch which was a PITA and it work like new and even made the lights brighter. It cost me $20 , from discount auto.
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fuse , headlight switch , relay

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