Off road lighting question

RSalani · 07-23-2008, 06:41 PM

So I have a 1987 Chevy Stepside. I have 4- 100 watt KC lights on the bull bars on the front of the truck. There are pictures of it floating around the site, but i am too lazy to go find the link at the moment. Anyway, They have a 30amp relay wired in, and a fuse block by the battery. I have tried up to a 40 amp fuse, and they keep blowing instantly. I tried re-wiring them, but it still happens. ANy pointers???

junior3382 · 07-23-2008, 06:50 PM

Could be a wire crossed or a unescesary ground in the circut. Sounds like that to me though. I have never wired up off road lights, not yet anyways, but I had the exact problem with an amp one time. Turned out for me, when I pulled the power wire through the firwall, it pulled some of the insulation off the wire and grounded out right there. Power went straight from the batt to a ground and kept blowing fuses. And those amp fuses are not cheap! LOL... anyways, long way of saying, it sounds like a crossed wire or the lead wire is grounded.....

mudseeker · 07-23-2008, 07:09 PM

do you have the relay wired right? you may have the ground wire in the wrong spot.

75K30 · 07-23-2008, 08:24 PM

Do you have all 4 lights wired to one relay? Single relays are designed to operate up to two (100W) lights only.
That is only a 30 amp relay, and if you have 100 W bulbs, then you have exceeded the rating of the relay, and close to the limits of the fuse.
A 100W bulb will have over 8 amps of draw, and if multipled by 4 is greater than 33.2 amps. If you no not blow the relay soon, you will.
You will have to wire two relays in parallel to split the amperage load. This can still be operated by one switch, you just have to tie the relay coil wires together (parallel) and activate by a common switch, so they all light up at the same time.
Do also make sure that you have large enough wire to accomodate this load. You should expect at least 14 AWG MTW wire.
Good connections are critical. Make sure none of the connections are just twisted together. Use solder joints whenever possible, and try to keep moisture out of the joint.
Spread your load (provided you do not have a dead short) and you should be good to go.

RSalani · 07-23-2008, 10:38 PM

Thanks guys!! I will have to do some more tinkering tomorrow, hopefully it will work out

07-23-2008, 06:41 PM	#1
RSalani Full Member Join Date: May 2008 Posts: 25	Off road lighting question So I have a 1987 Chevy Stepside. I have 4- 100 watt KC lights on the bull bars on the front of the truck. There are pictures of it floating around the site, but i am too lazy to go find the link at the moment. Anyway, They have a 30amp relay wired in, and a fuse block by the battery. I have tried up to a 40 amp fuse, and they keep blowing instantly. I tried re-wiring them, but it still happens. ANy pointers???

07-23-2008, 06:50 PM	#2
junior3382 Senior Member Join Date: Mar 2007 Location: Currently, I live in Lancaster county, Pennsylvania. Posts: 3,040	Could be a wire crossed or a unescesary ground in the circut. Sounds like that to me though. I have never wired up off road lights, not yet anyways, but I had the exact problem with an amp one time. Turned out for me, when I pulled the power wire through the firwall, it pulled some of the insulation off the wire and grounded out right there. Power went straight from the batt to a ground and kept blowing fuses. And those amp fuses are not cheap! LOL... anyways, long way of saying, it sounds like a crossed wire or the lead wire is grounded..... __________________ *Parts have been found, tools are collecting, tensions are rising, the weather is changing...look out.... the SAS is comming!*

07-23-2008, 07:09 PM	#3
mudseeker mod-o-tator Join Date: Feb 2006 Location: michigan Posts: 4,508	do you have the relay wired right? you may have the ground wire in the wrong spot. __________________ member map add yourself alldatadiy why is it, when i push one for english, i still can't understand the person on the other end?

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07-23-2008, 08:24 PM	#4
75K30 Senior Member Join Date: Jul 2006 Posts: 2,630	Do you have all 4 lights wired to one relay? Single relays are designed to operate up to two (100W) lights only. That is only a 30 amp relay, and if you have 100 W bulbs, then you have exceeded the rating of the relay, and close to the limits of the fuse. A 100W bulb will have over 8 amps of draw, and if multipled by 4 is greater than 33.2 amps. If you no not blow the relay soon, you will. You will have to wire two relays in parallel to split the amperage load. This can still be operated by one switch, you just have to tie the relay coil wires together (parallel) and activate by a common switch, so they all light up at the same time. Do also make sure that you have large enough wire to accomodate this load. You should expect at least 14 AWG MTW wire. Good connections are critical. Make sure none of the connections are just twisted together. Use solder joints whenever possible, and try to keep moisture out of the joint. Spread your load (provided you do not have a dead short) and you should be good to go.

07-23-2008, 10:38 PM	#5
RSalani Full Member Join Date: May 2008 Posts: 25	Thanks guys!! I will have to do some more tinkering tomorrow, hopefully it will work out