No low beam lights

[Schgsd]

Hi all, I'm here with the same issue. Have been reading this post and trying what has been suggested. High beams work. Parking lights work. I can hear the relays for those click. No click for the low beams. Swapped the relay with the high beam relay. High beams still work, no low beams. So relay is fine. Fuse 4 and 5 are good. Bulbs are good. I jumped 12v to the side of fuse 4 or 5 that goes out to the bulbs. They both light. Ground from the bulb connectors tests good. Service manual shows pin 3 of the relay as being always hot. And I found 12v there. (And 12v at pin 3 for the high beams). Based on that I sported for a new multifunction switch based on it failing a test I found in Identifix that showed I needed to see a certain range of ohms on pins 4 and 5 of the connector from the multifunction switch. The thing is it didn't completely fail but Identifix said if any part of it fails replace the switch. I now have a new $80 multifunction switch and a spare that's probably good cause NO Low Beams.

What I've just done is solder a wire to pin 2 of the relay which is the 86 referenced by Billwill and plugged the relay back in. Touched the other end to ground, a bolt under the steering column. The relay triggers and low beams go on.

 

[Billwill]

Welcome to the Forum!

What year/model do you have...need this to be able to go through correct wiring diagram with you.

Do you have a Canadian model?
These have slightly different headlamp wiring in that there is the Large Daylight Running Light Relay in the top left position of the interior fuse panel (Junction Block).

Did you locate the Low Beam Relay on the reverse side of this Junction Block?

 

[Schgsd]

Welcome to the Forum!

What year/model do you have...need this to be able to go through correct wiring diagram with you.

Do you have a Canadian model?
These have slightly different headlamp wiring in that there is the Large Daylight Running Light Relay in the top left position of the interior fuse panel (Junction Block).

Dis you locate the Low Beam Relay on the reverse side of this Junction Block?

Hi Bill. this is a 2005 US model no fog lights. No DRL. 3.7L 6 cyl And yes not only have I located the low beam relay I swapped it with the known working HiBeam relay as part of my testing. Lot of fun getting at it, couldn't be a harder to reach relay in the entire vehicle I think. Low Beams go on when I ground #86 on the wiring diagram.

 

[Billwill]

OK I hope you have downloaded the 2005 Jeep KJ Service Manual here:

www.colorado4wheel.com/manuals/Jeep/KJ/

Section 8W is the wiring diagrams.

Page 8w-45-3 shows part of the BCM which is the module that plugs on the rear side of the Junction Block. Your Pin #86 of the Low Beam Relay goes into the BCM directly at JB pin 13.

With battery disconnected, try re-plug the BCM on and off of the Junction Block a few times in case the JB Pin 13 has a dirty contact. While the BCM is unplugged, check for continuity from your Low Beam Relay Pin 86 to JB 13 on the Junction Block.

Otherwise you will need to trace the three wires shown on 8W-45-3 going from the Multi-Function switch to the BCM connector C2 pins 5, 4 and 19 for continuity.

In other words the Pink/Red wire, the White/Yellow/ and the other White/Yellow?...may be an error here...not uncommon!

Basically when the High Beam is toggled ON the BCM senses through these three wires that it must turn the Low Beam Relay OFF and when the High Beam Relay is toggled OFF the Low Beam relay should be turned ON...this is not happening!

This may be difficult problem to find if the above actions do not correct the problem!

 

[Schgsd]

Yes, first thing I did was grab that service manual from the link you posted.

I see 3 connector blocks up in there under the dash and found another when I dropped the low beam relay and it fell behind the plastic kick panel below them. Which one is for the BCM on the junction block?

 

[Billwill]

Yes, first thing I did was grab that service manual from the link you posted.

I see 3 connector blocks up in there under the dash and found another when I dropped the low beam relay and it fell behind the plastic kick panel below them. Which one is for the BCM on the junction block?

The BCM plugs directly onto the Junction Block...that is why the Low Beam Relay on 8W-45-3 does not show any cable colors for the connection to JB13 for example....directly connected on the Junction Block itself.

Section 8E Electronic Control Modules Page 5 shows how to remove the BCM from the Junction Block. Once you have removed it, measure continuity from Low Beam Relay pin 86 to the empty slot where the BCM was ie. JB pin #13.

That continuity should definitely be there!
Maybe when you plug the BCM back onto the Junction Block any dirty contacts will have been cleaned up.

8W-80-79 onwards shows the layout of the connectors on the Junction Block...connector C2 is the one you will need to measure the cabling from the malfunction switch to the C2 connector...best to go by the wire colors ie. Pink/Red stripe, White/Yellow stripe and the third unknown color wire!

Once you have it all put back together and you need to measure the voltages on the three wires coming from the switch..best to tape a pin/needle to the Red meter probe to piece the insulation on the wires and hit the copper inside. You can close the holes in the insulation later with some glue.

The BCM itself is a Black Box ie. no wiring diagram for what goes on inside...same as all the other Electronic Modules!

 

[Schgsd]

OK so busy with family stuff this weekend, hoping to find time to check out what you have told me in the last reply. Need low beams so I can drive it so I have a quick fix in place that still uses the relay for the low beams. Taking the wire I soldered to #86 and connected it to a switch and then the other side of the switch wire is soldered to an eye connector that is bolted under the left side of the frame for the steering column which is a solid ground. Lights go on and off as needed.

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[Schgsd]

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[Schgsd]

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[Schgsd]

Having been really in and under the dash now I see the BCM connectors on the back side of the fuse block. As soon as I get a chance next week I'll be in there and try to back probe the connections and see what I find.

 

[Cupcake]

I'm having the same problem with my 2006 Jeep Liberty. My low beams are going off intermittently. I replaced the multi-function switch and it didn't do anything so I put the original back in. I replaced the lowbeams relay and that worked but now a couple of days later it started turning off by itself again. What else can it possibly be??

Replace the multi-function switch and replace the new relay again?

 

[Schgsd]

My suspicion would be you have the same problem I have. With the info from BillWill my guess is (1) the BCM isn't being told to turn on the low beams, or (2) the bcm is trying to put the coil side of the relay to ground and that part of the circuit is bad. My guess would be #1 because #2 is a direct connection on the block housing all the relays so less chance of a bad or corroded wire here. A new MFSw was no help in my case. Pull the low beam relay, it's a bitch to get as it's way up top on the block. Mine had a circuit diagram of the relay right on the relay case. Find the pin listed as #86. Get a wire on it and plug it back in. Take the other end of that wire on the relay and touch it to a good ground. You should hear your relay click and your low beams should light up. What I have done is create a little circuit with that switch I mounted in the dash panel so I can do that and have my lights work until I get time to screw myself up into a pretzel and get under the dash and start testing the connector block to the BCM per BillWills info and see what has failed. I think I will find a bad connection in the harness between the multifunction switch and the BCM.

FYI the high beam relay that is on the panel with all the fuses under the cover left side of the dash is the same relay as the low beam relay.

 

[Billwill]

I'm having the same problem with my 2006 Jeep Liberty. My low beams are going off intermittently. I replaced the multi-function switch and it didn't do anything so I put the original back in. I replaced the lowbeams relay and that worked but now a couple of days later it started turning off by itself again. What else can it possibly be??

Replace the multi-function switch and replace the new relay again?

The fact that things worked for a while after you replaced the Low Beam Relay would indicate a loose connection in the area of the Junction Block where the relays are connected. Bumping the connectors around while replacing the relay temporarily makes good contact until going over a bump in the road which loosens the contact.

You need to re-plug all the connectors going to the Junction Block where all the relays plug in and have a good look at the female contacts inside the Low Beam Relay socket...the female contacts can be pulled apart so that they do not clamp onto the male relay contacts firmly.

 

[Cupcake]

An update to this. The junction block was bad and had to be replaced. ***** as it was rather costly but in case anyone comes across this thread in the future -- if its not the multi-function switch and it's not the relay -- you might have a bad junction block. A used junction block runs like $75 but I needed a mechanic to install it as this was above my pay grade.

 

[Schgsd]

Ugh, thank you for the update. I am still running on my redneck engineered switch that puts ground to the relay. But a recent mishap has me now in need of a driver side exterior mirror assembly so I think I will be doing some Christmas shopping at a local salvage yard.

 

[JoDun1975]

hello to all just joined. I have a 2005 Jeep Liberty sport 4x4!
All lights work and function as they should except for low beams.
Garage I sent it to said could be light control module. What is it and where is it?
I have a manual and have looked on line but cannot find this elusive part.
All suggestions welcome.
Paul

It's called a multi function switch. Very easy change, just 2 screws, but first check the fuse & relay! Good Luck!! I'm a female and had no problem changing out the multifunction switch so if I can do it, anyone can!!