Headlights not turning on until engine warms

John in CO

John in CO

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Joined
Oct 9, 2021
Messages
2
Location
Fort Collins, CO
So this is more of a winter/cold weather issue. And it's very odd.

I have a 98 TJ Sport with numerous electrical issues (fuses blowing constantly) but this is more about the headlights not turning on until the engine warms up when it's below freezing. Not a big deal right now, getting into summer, but it'll be an issue again next winter.

All the other lights will work — turn signals, brakes, parking lights — but when it's really cold out the headlights won't turn on until the engine gets up to temp. Not a huge deal, it's a 5 minute wait most nights, but I feel like there will come a day (night) when it's really cold and I'll have to drive home from work w/out headlights, hazard lights blinking. So I'm trying to fix it.

Is there a relay somewhere that needs to be replaced? Any thoughts or suggestions are much appreciated.
 
I don't think it's the switch. The dimmer works just fine, all the other lights work fine. It's just the headlights not turning on until the engine temp gets to 185.

Like I said, it's odd. I don't think it's the headlights themselves because both turn on at the exact same time. Which is why I wonder if it's a relay somewhere?
 
Check the wiring schematics in the 1998 FSM in section 8W; there does not appear to be a relay in the 8W-50-2,3,4,5,6,7.
There is a 24A circuit breaker that supplies power to the Dimmer Switch for the Lo/Hi beams.
Check the grounds in the engine compartment near the radiator and fender wells along with wiring in connector C110.

https://wranglertjforum.com/attachments/1998-tj-service-manual-pdf.14033/
 
Been there done that on 2 Cherokees and my 99 TJ it's the headlight switch.
It really sucked when I was going into work a 3:30 am for snow removal and the headlights wouldn't come on , only the parking lights even with the switch all the way out. For giggles I turned the dimmer rheostat most of the way down to put more heat into the switch, (which did help ).
But the cold light problem will go away replacing the switch !
 
You have an intermittent electrical connection. Reseat (unplug/plug back in) both headlight connectors several times. Then remove both headlight connector black ground connection wires where they attach to the tub with a screws, wire brush their connection points, then securely reattach them.

If that doesn't help replace the headlight switch. It's a very simple circuit, no relay is in it.
 
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John in CO said:
So this is more of a winter/cold weather issue. And it's very odd.

I have a 98 TJ Sport with numerous electrical issues (fuses blowing constantly) but this is more about the headlights not turning on until the engine warms up when it's below freezing. Not a big deal right now, getting into summer, but it'll be an issue again next winter.

All the other lights will work — turn signals, brakes, parking lights — but when it's really cold out the headlights won't turn on until the engine gets up to temp. Not a huge deal, it's a 5 minute wait most nights, but I feel like there will come a day (night) when it's really cold and I'll have to drive home from work w/out headlights, hazard lights blinking. So I'm trying to fix it.

Is there a relay somewhere that needs to be replaced? Any th
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Welcome John !, I know this seems weird, but I have had the same problem on 3 different Jeeps with the pull out style switches. They will work fine in warm weather OR after the Jeep interior warms up. But in cold weather you pull the switch to the headlight position and only the park, tail and dash lights work. After the Jeep warms up the headlights will come on. I believe contacts in the switch "stick" or hang up internally when cold with the old faulty switch. I had this problem in a 94 and 99 Cherokee and my 99 TJ , all three the fixed by simply replacing the headlight switch. Folks that live in sub tropical areas have likely never experienced this issue. ;)
 
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