Dimming Headlights

[gornoman]

It was a longshot anyway.

[SandbaggerYDRA]

Originally Posted by Ronv27

Taillights are a sealed unit, all i can do is unplug them and then all the other lights don't dim

Something isn't right. Tail lights do not draw nearly as much as headlamps do. I have brake lights on my cart and they don't affect the other lights at all when they are applied.

Either you have a short somewhere when the brakes are applied, or there is a resistance in the power or ground wires that supply the power to the lamps that are dimming. You can measure the voltage at the battery to see if it drops when the lights dim. If not, you have a resistance somewhere. It may be as simple as too small a gauge of wire leading to the lamps. Or it could be corroded connections to the battery or whatever the source of power or ground.

[cgtech]

Try the tail lights one-at-a-time on each side to see if you can narrow it down to 1 bad unit or bad wiring.

[LimitedEdition]

If you haven’t changed or modified the original wiring (adding turn signals or clearance lights) then it is going to be a bad connection or broken wire in the wiring harness. Electricity looks for the least path of resistance to complete a circuit. Even if it has to back feed through other light bulbs in the circuit and that is why the bulbs might be dimming. The lights normally get 12v each in a good circuit but if there is an open in the circuit then they could be trying to complete their connection by back feeding through the other lights in the circuit. This would put the taillights in series with the other lights and the 12v would be dropped to each bulb making them dim. I believe if there was a short somewhere then you would have a blown fuse or melted wires. Good Luck.
Robert

[sho305]

Yes make sure you have good grounds back to the battery, ones that do not use cart wiring (unless the lights are stock). Figure that out, and then sure I'd recommend you use any LED lighting you can on the cart to save power, though not required.

Brake lights can take a fair amount of power, but with a good battery you are talking about dimming not 'real dim'. It will dim when you take your foot off the gas because it stops charging and you go from 13.5v to 12v on battery. Then it may dim slightly more as the tail lights load the battery more when you press the brake (plus the headlights are on yet) but it should not drop that much from 12v if battery is good. If you have a wiring/ground issue you would see less voltage at the light, or see voltage in the ground as compared to the battery ground indicating a ground fault. You can also test across the light and should have the same or very close to battery voltage (while light is on, will be similar to battery voltage with lights on). The difference would be wire loss and it should be minimal, like tenths of a volt.

[gornoman]

Originally Posted by LimitedEdition

The lights normally get 12v each in a good circuit but if there is an open in the circuit then they could be trying to complete their connection by back feeding through the other lights in the circuit. This would put the taillights in series with the other lights ......

This is where I was headed.

[Ronv27]

I went through all wires that i could, cleaned all grounds, cleaned positive connections and checked all connections i could. When i replaced the rear taillights with LED lights all problems were fixed. Thank you to everyone that helped.
Ronv27

[sho305]

Interesting, this place is saying 28w for a common 1157 brake light and another 8w for the running light part. So that is 56w you turn on with the brake pedal, or a about a single 55w driving light commonly used for headlights on carts. LED look to be about 2w each.