Headlight relay?

  • #1

howdy all,

my wife’s ’03 has an intermittent issue where the headlights will blink off for a second or two then come back on. the flicking on & off is accompanied by a clicking sound in the dash that sounds like a relay cycling. is there a relay for the headlights that might be on its way out?

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  • #2

when the headlight switch is turned on, it send voltage (usually negative and less than 12 volts) to the bcm (body control module). the bcm will then send voltage (-) to a relay with a built in resistor. from there the voltage goes to the headlight bulbs to illuminate them.

here’s the fsm (factory service manual):

http://www.colorado4wheel.com/manuals/jeep/kj/2003jeepkjservicemanual.pdf

section 8w is electrical

section 8w-50-1 is front lamps

  • #4

  • #5

so there’s a low and high beam relay then. are these common replacement items?

they are pretty robust but can fail.

there are lots of identical relays present on the junction block which is the name for the fuse panel….high beam relay is the only small relay on the front of the panel while there are several identical relays on the reverse side….swap them around!

canadian model have a large relay at top left of the fuse panel which is for daylight running mode and is interconnected to the high/low relays.

i am more inclined to suspect the multifunction switch which does fail often or bad connections on the bcm which is the module on the rear of the junction block.

  • #6

they are pretty robust but can fail.

there are lots of identical relays present on the junction block which is the name for the fuse panel….high beam relay is the only small relay on the front of the panel while there are several identical relays on the reverse side….swap them around!

i am more inclined to suspect the multifunction switch which does fail often or bad connections on the bcm which is the module on the rear of the junction block.

the problem had gone away for a while, but is back. the other night the headlights shut off for 2-3 seconds on the highway. the problem is sporadic, so swapping relays on the jb might not identify the problem right away. what/where is the multifunction switch?

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  • #7

the problem had gone away for a while, but is back. the other night the headlights shut off for 2-3 seconds on the highway. the problem is sporadic, so swapping relays on the jb might not identify the problem right away. what/where is the multifunction switch?

the multifunction switch is the switch that has the stalks on either side for turn signals and headlights etc. so you need to remove the plastic cover at the top of the steering column…no need to disconnect the battery.

then the multifunction switch lifts up…remove one connector if i remember correctly!

when replacing the assembly get the correct one for either front fog lamps or not!

unfortunately this may not fix your problem..could be a bad ground for the front lights or other wiring problems. you would need to climb into the wiring diagrams to trace that but replace the multifunction switch first!

  • #8

mine was doing that and a new multi function switch fixed it but now it randomly turns on the interior lights…

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Category: Headlights