Head lights: High-beams work great, low-beams not so much

ftalge · 09-20-2007, 12:20 AM

I have a 2001 Ram 3500 Sport that refuses to show its low beams. All the other lights work (including the high-beams). The dashboard switch checks out fine and I have even replaced the multi-function switch in the steering column. No fuses are blown.

All suggestions are appreciated.

Thanks

mudseeker · 09-20-2007, 08:42 AM

have you cleaned the connections at the lights and applied some dielectric grease? i always check the ceapest things first and light bulbs are at the top of the list.

75K30 · 09-20-2007, 09:19 AM

The above recomendation is very good. start with the easiest things and work from there eliminating the little stuff. since the two bulbs are bad it would appear to be more than coincidence.
Your multi function switch energizes a relay the drives the high / low beams. It is wired as a form "c" contact meaning that the low beans are on a normally closed circuit, and the high beams on a normally open. When the multi function switch is pulled, it energizes the coil in the relay, changing the states of the realy. The low beam becomes open, and the high beam now becomes closed. the problem is either a bad leg in the realy (low beam side) or a bad supply voltage. This supply voltage could be before, or after the relay. This would indicate a bad wire, but testing the relay will give you a direction to continue troubleshooting.
Relays seldom loose one leg, but it is possible. You can verify this by installing another relay known to be good. Your truck is full of them, and they are interchangeable. they just plug in. Simply find one that is the same and install it. They should be marked "OMRON" or "Bosch". If you replace it and it works, you have found the problem, if it does not, you will need to continue on, but this would indicate that the problem is between the relay and the bulb, like a broken wire.
Good luck, electrical is sooooo much fun.

crabtruck · 09-20-2007, 05:20 PM

By the way, how are your DRLs?

ftalge · 09-20-2007, 11:40 PM

Quote:

Originally Posted by crabtruck

By the way, how are your DRLs?

The "running lights" are working.

09-20-2007, 12:20 AM	#1
ftalge Junior Member Join Date: Sep 2007 Posts: 3	Head lights: High-beams work great, low-beams not so much I have a 2001 Ram 3500 Sport that refuses to show its low beams. All the other lights work (including the high-beams). The dashboard switch checks out fine and I have even replaced the multi-function switch in the steering column. No fuses are blown. All suggestions are appreciated. Thanks

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09-20-2007, 08:42 AM	#2
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 7,128	have you cleaned the connections at the lights and applied some dielectric grease? i always check the ceapest things first and light bulbs are at the top of the list.

09-20-2007, 09:19 AM	#3
75K30 Senior Member Join Date: Jul 2006 Posts: 3,292	The above recomendation is very good. start with the easiest things and work from there eliminating the little stuff. since the two bulbs are bad it would appear to be more than coincidence. Your multi function switch energizes a relay the drives the high / low beams. It is wired as a form "c" contact meaning that the low beans are on a normally closed circuit, and the high beams on a normally open. When the multi function switch is pulled, it energizes the coil in the relay, changing the states of the realy. The low beam becomes open, and the high beam now becomes closed. the problem is either a bad leg in the realy (low beam side) or a bad supply voltage. This supply voltage could be before, or after the relay. This would indicate a bad wire, but testing the relay will give you a direction to continue troubleshooting. Relays seldom loose one leg, but it is possible. You can verify this by installing another relay known to be good. Your truck is full of them, and they are interchangeable. they just plug in. Simply find one that is the same and install it. They should be marked "OMRON" or "Bosch". If you replace it and it works, you have found the problem, if it does not, you will need to continue on, but this would indicate that the problem is between the relay and the bulb, like a broken wire. Good luck, electrical is sooooo much fun.

09-20-2007, 05:20 PM	#4
crabtruck Senior Member Join Date: Jul 2007 Posts: 4,079	By the way, how are your DRLs?