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Low beam headlights not working

Tiny
DINESH GOSAIN
  • MEMBER
  • 2003 JEEP LIBERTY
  • 3.7L
  • V6
  • 2WD
  • MANUAL
  • 114,000 MILES
The low headlights don't work, high beam works fine, bulbs are good, the fuses for low beams are not lighting up with the probe. Also swapped relay switch.
Thursday, June 9th, 2022 AT 9:57 AM

48 Replies

Tiny
BORIS K
  • MECHANIC
  • 795 POSTS
Hello,

The low beam relay is powered by fuse 15, 50A, in the power distribution center (PDC).
Constant 12V is transmitted on the red/tan wire to pin 1 at connector C3.
See image 1 below.
The first thing to check is if the horn is working as the horn fuse and relay are also powered by the same fuse, see image 2 below.
If the horn is working, provided you are still using the factory horn, then the next thing to check would be if you have constant 12V at terminals 30+86at the low beam relay socket.
This can be done using either a test light or a voltmeter.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester
and
https://www.2carpros.com/articles/how-to-use-a-voltmeter

If 12V is present at both terminals then next check if a ground is switched on when the headlights are switched on at terminal 85, see image 1 below.

Next check continuity from relay terminal 87 to either fuse F4 or F5, see image 3 below.
This can be done using a voltmeter, digital multimeter.

https://www.2carpros.com/articles/how-to-check-wiring

Hope this helps.

Cheers, Boris
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Friday, June 10th, 2022 AT 1:06 AM
Tiny
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In my Haynes book for the vehicle listed above I found the wiring schematics on page 12-8. Wiring charts are very intimidating and very, very hard to understand. I followed the first diagram and checked fuse 15 and 50 in the fuse box under the hood.
Actually, I pulled out all the mini fuses and checked to see if any were blown. They were all good. Then I checked the other fuse 50 and it looked fine also. It did not look blown. I decided to swap the fuses with other fuses, and no change.

My test light is the same as yours in one of the photos. I also used a voltmeter. I had jerry-rigged the wires to have a low beam. I took the low beam light wire and removed it from the bulb socket, and I put the high beam wires in the low beam in the bulb socket. It works, but I have to get my car inspection this month and I don't think this is going to work. The fuses 4 and 5 for the low beam still don't light up with the probe. So, fuses 4 and 5 show now activity. I had mentioned in my first post that I had swapped the relay switches. So, the switch makes a clicking noise and we know both high and low beam switches work. I don't have power to the low beam fuses and when the low beam wire was checked at the bulb socket wire. This is the only car I have to drive and I can't drive at night.

Please, please help me.
Dinesh
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Monday, June 13th, 2022 AT 2:15 PM
Tiny
BORIS K
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Hello,

Just to clarify, when you switch on the low beam lights the low beam relay clicks.
If so, then there seems to be an internal failure in the junction block.
As a last try you could bridge the low beam relay terminals 30+87, with the low beams wired up as original the low beams should work, meaning fuses 4+5 will have power. If there was still no power this would definitely point to an internal junction block failure.

Cheers, Boris
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Tuesday, June 14th, 2022 AT 12:28 AM
Tiny
DINESH GOSAIN
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Hello Mr. Boris,

I tested the low beam relay out of the junction box and listened very carefully for the click sound which opens and closes the relay. You know I swapped the relays from high to low and low to high. I put the high beam relay in the low beam relay position and I took the low beam relay and put it in the high beam relay. When I turned on the lights, no low beam, when I turned on the fog lights they came on and when I turned on the high beam lights they worked. This means the relays are not the issue? I don't know. I think you can answer that better. I'm going to go out to the car and start from the beginning again. I haven't looked up the ground for the wiring harness yet. I don't know where that would be.
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Tuesday, June 14th, 2022 AT 6:10 AM
Tiny
DINESH GOSAIN
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Mr. Borins K,

Since I'm going to start from the beginning, I was wondering you could provide the steps I should take from 1?
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Tuesday, June 14th, 2022 AT 7:16 AM
Tiny
BORIS K
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Hello,

First ensure that you have constant 12V at terminals 30+85. Check this by using either a test light or a voltmeter with the low beam relay removed.

How to use a voltmeter:
https://www.2carpros.com/articles/how-to-use-a-voltmeter

The ground is switched by the body control module at terminal 86 at the low beam relay socket. The easy way to test this is to use a test light connected to 12V (battery positive) and touch terminal 86 with the relay removed. Switch the low beam lights on and the body control module should switch a ground to this terminal and the test light will light up.

How to use a test light:
https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

To test the integrity of the internal circuit of the junction block I would suggest to bridge terminal 30 with 87. This in turn should energize both fuse 4+5 and light up the low beam lights.

See illustration below.

Hope this helps.

Cheers, Boris
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Tuesday, June 14th, 2022 AT 8:54 AM
Tiny
DINESH GOSAIN
  • MEMBER
  • 75 POSTS
  • 2003 JEEP LIBERTY
  • 3.7L
  • V6
  • 2WD
  • MANUAL
  • 114,000 MILES
In my Haynes book for the vehicle listed above I found the wiring schematics on page 12-8. Wiring charts are very intimidating and very, very hard to understand. I followed the first diagram and checked fuse 15 and 50 in the fuse box under the hood.
Actually, I pulled out all the mini fuses and checked to see if any were blown. They were all good. Then I checked the other fuse 50 and it looked fine also. It did not look blown. I decided to swap the fuses with other fuses, and no change.

My test light is the same as yours in one of the photos. I also used a voltmeter. I had jerry-rigged the wires to have a low beam. I took the low beam light wire and removed it from the bulb socket, and I put the high beam wires in the low beam in the bulb socket. It works, but I have to get my car inspection this month and I don't think this is going to work. The fuses 4 and 5 for the low beam still don't light up with the probe. So, fuses 4 and 5 show now activity. I had mentioned in my first post that I had swapped the relay switches. So, the switch makes a clicking noise and we know both high and low beam switches work. I don't have power to the low beam fuses and when the low beam wire was checked at the bulb socket wire. This is the only car I have to drive and I can't drive at night.

Please, please help me.
Dinesh
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Tuesday, June 14th, 2022 AT 11:24 AM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Power to both fuses 4 and 5 comes from fuse 15 (50 amp). However, for the power to reach fuses 4 and 5, it must pass through the low beam relay. Have you checked the relay? If not, remove the low beam relay and switch it with a different relay from the box having the same part number. If there isn't one, here is a link that explains how to test a relay.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

I attached the schematic I have below. If you have questions about it, let me know what they are. Also, keep in mind, if fuse 15 is good, power is there at the relay. For the switch in the relay to close and send power to fuses 4 and 5, a ground path has to be provided to the primary side of the relay by the body control module. We could have an issue there as well. I highlighted the BCM wiring, and I placed an arrow showing the power flow from fuse 15.

I will watch for your reply.

Take care,

Joe

See pics below.
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Tuesday, June 14th, 2022 AT 11:24 AM (Merged)
Tiny
DINESH GOSAIN
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I tested the low beam relay out of the junction box and listened very carefully for the click sound which opens and closes the relay. You know I swapped the relays from high to low and low to high. I put the high beam relay in the low beam relay position and I took the low beam relay and put it in the high beam relay. When I turned on the lights, no low beam, when I turned on the fog lights they came on and when I turned on the high beam lights they worked. This means the relays are not the issue? I don't know. I think you can answer that better. I'm going to go out to the car and start from the beginning again. I haven't looked up the ground for the wiring harness yet. I don't know where that would be.
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Tuesday, June 14th, 2022 AT 11:24 AM (Merged)
Tiny
DINESH GOSAIN
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Hello Mr. Boris,

Ah, when I said that I heard the click on the relay I would disregard that. Sorry about that. I removed the low beam relay from underneath the dash. I followed your instructions to test the relay "First ensure that you have constant 12V at terminals 30+85. Check this by using either a test light or a voltmeter with the low beam relay removed." I used two different voltmeters and I got 000 not 12V. Perhaps I did this wrong. Terminal 86 did not light up either with light tester connected to the positive terminal of the battery. I also pulled out the high beam relay to perform the same test on that and I got nothing on that relay as well.
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Tuesday, June 14th, 2022 AT 1:30 PM
Tiny
DINESH GOSAIN
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Mr. Boris,

I've attached some pics so you would know what I'm
looking at. I pray this helps you.

Thank you,
Dinesh
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Wednesday, June 15th, 2022 AT 3:53 AM
Tiny
DINESH GOSAIN
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Joe F,

I've attached some pics so you would know what I'm
looking at. I pray this helps you.

Thank you,
Dinesh
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Thursday, June 16th, 2022 AT 10:29 AM
Tiny
DINESH GOSAIN
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I installed a new relay and no low beam lights. Fuses 4 and 5 do not light up. Boris, I don't know how to do what you're asking. To test the integrity of the internal circuit of the junction block I would suggest bridging terminal 30 with 87. This in turn should energize both fuse 4+5 and light up the low beam lights. Yeah, I don't how to do what you're asking? Bridge terminal 30 with 87. I don't understand that. My low beam wire is purple in color on the driver's side. They seem to be routed to the front of the car.
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Thursday, June 16th, 2022 AT 1:50 PM
Tiny
CARADIODOC
  • MECHANIC
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Allow me to add a comment here. If someone asked you to bridge, or jump a relay, they mean use a piece of wire or a stretched-out paper clip to connect the two terminals for the relay's contacts. You're doing manually what relays do when they're energized. That powers up the circuit to allow you to work on it or take voltage readings.

When you poke anything into the terminals in the socket, be careful to not use anything fat enough to stretch those terminals. That can lead to intermittent problems later.

The relay in the top left of this drawing is the most common one used in Chrysler products. The others I drew here were also used in some models.
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Thursday, June 16th, 2022 AT 8:10 PM
Tiny
DINESH GOSAIN
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Thank you, Randy B, in your drawing I have the middle 5pin relay. I think there's an image of the relay I have forwarded. So put a paper clip in the two terminals 30+85 to see if I get a 12V on a probe that lights up and then check to see if fuses 4 and 5 light up in the fuse panel.

I didn't mention this earlier, because I didn't think that the radio would cause my low beam lights not to work. The radio has gotten old, and I thought it went out. All the fuses for the radio are in different places, not with any light system fuses.
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Friday, June 17th, 2022 AT 2:38 PM
Tiny
CARADIODOC
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If you have the skinnier relay in the top middle of my drawing, jump the two larger terminals with the arrows pointing to them.

When a relay has terminals designated as "85" and "86", those or for the coil that activates the relay. "87" and "30" are for the relay's contacts, meaning the switch part of it. That's what we need to jumper to in effect, turn the switch on.
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Friday, June 17th, 2022 AT 2:45 PM
Tiny
DINESH GOSAIN
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So, 30+85 like in the photo below and you said 87+30. Two different connections.
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Friday, June 17th, 2022 AT 3:54 PM
Tiny
CARADIODOC
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I don't know where the confusion came from, but terminal 85 is not part of this story. That's in the control circuit as one of the two terminals for the relay's coil. It's 30 and 87 you want to jump together.

As a point of interest, and to confuse you even more, when the relay in your drawing is not energized, terminals 87A and 30 are connected internally. That condition, meaning terminal 87A, is rarely used in any car model. Many relays don't even have terminal 87A. They have just four terminals. When the coil is energized by putting 12 volts across it, the relay's movable contact flips. It leaves 87A and makes contact with terminal 87. That is the standard relay function used almost all of the time.
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Sunday, June 19th, 2022 AT 7:19 PM
Tiny
DINESH GOSAIN
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Hello Randy,

Over the weekend I removed the plastic cover to the relay and tested it with a 12v battery from one of my cordless drills. As I witnessed the relay click and move. I have a new relay that I purchased last week and installed it in my car. Even with a new relay the low beams don't come on. I was hoping that the new relay installed would fix it, but it didn't. I don't know what to do now. Any assistance would be appreciated.
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Monday, June 20th, 2022 AT 10:48 AM
Tiny
DINESH GOSAIN
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I just checked with a power tool battery and jumped 30+87, 30+87A and no clicks on the relay. I only get a relay click on 85+86. Nothing else gives me any clicks. This is the original relay from the car. I have a new relay in the car for the low beams and they still don't work. Even with the new relay fuse 4 and 5 don't light up.
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Monday, June 20th, 2022 AT 1:02 PM

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