The Stovebolt Site Forums The Shop Area The Electrical Bay Parking Light - Tail Light Relay

Tomorrow I am going to be adding a low beam/high beam relay harness for my headlights, which I have heard from multiple sources is a very good upgrade not just for brighter lights but to help the overall health of the electrical system.

I got to thinking, if relays help the headlights be brighter, wouldn't a relay for the parking lights and tail lights do the same for those lights? I have researched this over the last few days and haven't found anything good on the subject.

What are you guys thoughts on adding a relay for the parking lights and tail lights?

The headlights draw a lot more current than the tail lights. Sometimes the voltage drops, especially through the headlight switch really affect the headlight brightness. Using a relay takes care of that problem. I don't think you would see any difference adding a relay to the tail light or parking light circuits.

Okay, thanks. If I get bored and have nothing better to do some day, I may wire one in just for fun, but I like your reasoning on not seeing the same benefit as having relays for the headlights.

I agree with truckernix, it's not needed due to the low current draw and the relay just becomes another point for failure.

Mike B

LoweBoy;

Do you have a wiring diagram/schematic for your headlight relay harness. This sounds interesting and I'm trying to wrap my mind around how to do it. The quad headlights on my 58 Burb could probably benefit from such an arrangement.

I bought the harness from LMC and the relays are not numbered. After not knowing a thing about relays, I got Baptized by fire. I don't have a schematic of the harness but I can explain how it wired up.

I ran 10 gauge wire from the horn relay to a 20 amp maxi fuse. From there, each power wire for the relays were connected to the other side of the maxi fuse. The power is supplied to the "30" pin of each relay. The "85" pin receives the low beam signal from the dimmer switch, in this case it's the 18 gauge tan wire. This harness has two wires coming from the "87" pin, one for each headlight. The "86" pin is your relay grounds. For the high beam signal, it is the 16 gauge light green wire to the "85" pin of the second relay. And the second relay also has two wires going coming from its "87" pin, one for each headlight. This harness also came with the plugs for the headlights and a ground wire for each headlight. The harness came with a 3 prong plug that was supposed to plug into the plug at the radiator core support,but there are only 2 wires at the existing plug, so the 3 prong plug had to be eliminated. To further complicate things, this harness didn't come with correct colored wires, but by utilizing the shop manual wire diagrams, it was easier to figure out. Hope this helps. It's not a visual diagram, but a Google search will have many samples of diagrams.