[Jeep'n]

Hello Friends,

I have a 93' Merc. Grand Marquis. The Headlight switch is the push/pull type with dimming and auto "on" feature. The Problem is I have replaced this switch 3 times. Every time after about a month it fails, leaving either my headlights or taillights/dash lights not working. Currently my headlights work, but my tail lights + parking lights don't work. Here's some clues. Currently when I have my headlights on when I hit my blinker the headlights will turn out. Only a flip of my brights will turn them back on. Another clue. The plug that fits into the Headlight switch contains about 6 wires. The plug is semi melted on one spot due to heat. This is around the brown wire if that means anything to someone. All fuses are good. Any and all help will be greatly appreciated. Thanks!

[vicrod]

The most likely cause is the connections (plug) at the switch are not tight, which can cause overheating. Poor connections = heat. As the heat increases the connection gets worse because the resistance at the connection increases.

I'm assuming that no aftermarket lights have been added to the car. This can cause excessive (beyond the switch design) heat at the switch.

If the problem occurs after a time, say 10 minutes, the poor connection is the problem.

Check the tabs on the plug and connector for discoloration. Also, the crimped connection on the one of the wires may be bad. Or, was never done correctly from the factory.

Once these electrical connector are heated, they loose there spring and the problem gets worse.

You may need to replace the plug.

vicrod

[docvette]

Doc here,

Here is the diagram for your light switch:



If this is the 3 Rd switch, I'd check with the dealer first about recall notices..

First thing I'd do is get and replace that bad/Melted connector , the pins can be loose and vibrating, causing a Heating issue at the switch.

Check your high/low switch for a possible bad contact on the low selector. (although I should think the High/low would go out first)

Check ALL your lighting system grounds.

look for an intermittent or less than dead short on the lighting circuit.

Doc.

[Jeep'n]

Thanks for the help, I'll start by replacing the melted plug. I'll let you how this turns out.

Thank again