Dodge Ram: OEM switch/relay/wiring to aftermarket fog lights

Maintenance/Repairs
1

Hey everybody. I’ve got a question for the electrical wizards out there.

I have a 1998 Dodge Ram 1500 (Laramie SLT, 4WD Off-Road, 5.9L V8, Quad Cab) that came with in-bumper fog lights. The OEM light fixtures are garbage (the lenses always crack within a year or so), and I want to replace them with some kind of aftermarket fog light kit. I would like to use the already-installed OEM switch, relay, and most of the wiring, but I have one concern. The stock lights are 37.5 watts and all of the affordable aftermarket kits are 55 watts. Will it work? Will it fry the relay? Will it blow a fuse? What do you think?

Thanks for reading.

2

37W at 14V means it draws about (37/14=)2.5 Amps. 55W at 14V means it will be drawing about (55/14=) 4Amps.
Wiring tends to be fairly thick so can probably handle the extra bit of current. I strongly suspect you’ll be fine.

3

Your on the edge with this, the fog light wiring on these trucks is thin, 20 gauge. Compare to the headlight wiring, 16 gauge. You won’t get a full 14 volts to the bulbs with this thin wiring. You should use the wiring harness that comes in the fog lamp kit, you can find a way to use your factory dash switch to trigger the relay.

4

Nevada_545’s solution is the one I generally use. If the new lights don’t come with it, there are relay kits available to hook up these lights. Use the heavier wiring with the kit to hook the lights to the relay and feed the relay from a power tap off the battery (fused of course). Use the original wiring only to trigger the relay. The lights will get full voltage from the battery controlled by the relay, and the original wiring will have a lighter load to trigger the relay. This is all but guaranteed to protect your factory wiring from any damage due to higher wattage needs.

5

Thanks for the replies, everybody. I’ve got another question about the same application. I’m trying to go for the easiest and cheapest fix I can find. The new lights I’m looking at use a replaceable H3 bulb, and I can buy 35 watt bulbs that will fit (OEM lights were 37.5 watts). Would that be close enough that it ought to work?

6

I assumed the wire was beefy, around 16 gauge.
If the wire is only 20Ga, Navada is absolutely correct. 20 Ga is actually way too skimpy for running the two original 37W lights, imo.