Cab lights keep blowing fuses
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Cab lights keep blowing fuses
I recently added a set of cab lights to my truck and my buddy and i are sure everything is wired right but i keep blowing fuses and cant figure out why. Im running them on a seperate switch from my other lights to avoid any problems with my existing lights. I ran a relay in the circuit for themto reduce the draw on my battery. I ran a wire from the battery to terminal 30 On the relay with an inline fuse, terminal 87 to the lights, terminal 86 to ground, 85 to the on side of my switch, and the wire on the off side to a port in my fuse box. For some reason itbkeeps blowing the inline fuse from the battery. Doea anyone have an idea?
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I recently added a set of cab lights to my truck and my buddy and i are sure everything is wired right but i keep blowing fuses and cant figure out why. Im running them on a seperate switch from my other lights to avoid any problems with my existing lights. I ran a relay in the circuit for themto reduce the draw on my battery. I ran a wire from the battery to terminal 30 On the relay with an inline fuse, terminal 87 to the lights, terminal 86 to ground, 85 to the on side of my switch, and the wire on the off side to a port in my fuse box. For some reason itbkeeps blowing the inline fuse from the battery. Doea anyone have an idea?
what do you estimate to be the total wattage of the lights?
what fuse are you using for the lights?
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obviously something is wrong with the wiring...........
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Sadly i left my volt meter and test light in my tool box at work. The wires that feed the lights are all hooked in a series down to the relay, and everything else is like I mentioned in my first post. I do not know what went wrong.
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What brand/model are they? where did you get them from?
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have they ever worked?
do they fry instantly the fuse?
does it fry the fuse when driving?
could it be wire touching ground intermittently?
check amp draw when you get the chance?
check continuity to ground at positive lead?
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Idk if they work yet i just bought them but they're brand new and they only blow the fuse every time i turn them on. Id have to find the box to see the part number tho and ill check the amperage when i can
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85 and 86 are for the relay coil - 86 to incoming power, 85 to ground; you insert your on/off switch in this circuit.
Ford's wiring almost always puts the switches in the connections to ground but I'd guess what you're doing will work.
30, 87 and 87a are for the switched device
- 30 to incoming power
- 87a is connected to 30 with NO power to the coil
- 87 gets connected to 30 WITH an energized coil
Look at the horn relay in this diagram:
Relays
pedant
Joined: Jan 2008
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From: EXTREME southwest CT
Try the switch then.
If the fuse doesn't blow, your relay wiring is good.
What wattage are the bulbs?
Test the light's wire to ground for ohms.
The lights should be wired in parallel.
i.e. the wire going to the pin in the bottom of the socket 'Tees' off the main wire coming from the relay until you get to the last in the string of lights.
The bulb socket is always the ground side.
I suspect you have a socket wire connected to power.
And the mounting screws are grounding the socket too.
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pedant
Joined: Jan 2008
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From: EXTREME southwest CT
I asked about bulb wattage and ohms because -as you know- wiring resistors in series sums their individual values, wiring them in parallel is product over sum.
Patric Omalley did too.
http://en.wikipedia.org/wiki/Series_and_parallel_circuits
I still don't think that would be enough to blow a 30A fuse, but the OP is not forthcoming about the wattage or number of lights in the string.
Patric Omalley did too.
http://en.wikipedia.org/wiki/Series_and_parallel_circuits
I still don't think that would be enough to blow a 30A fuse, but the OP is not forthcoming about the wattage or number of lights in the string.
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