Backup lights blowing fuses

[captkidd]

The auxiliary backup lights that I installed on my truck keep blowing the inline fuse. I can't find any evidence of a short in the system, so what could be causing this? I'm wondering if the relay that I'm using could be at fault? I have the following connections running to it:

12V power wire from battery (with the aforementioned inline fuse)
power wire from the backup light in the taillight assy
ground wire from the frame
ground wire from the backup light in the taillight assy
power wire to the aux. backup lights

Does this sound right? I've been using a 20A fuse; could it be that this fuse just isn't big enough?

[88 PS190]

Are the new back up lights on the same circuit as the old ones?

If so you are trying to draw more load through the 20A fuse than was intended. Avoid increasing the amp load of the fuse until someone gives you a 100% certain answer, i've never done aux. back up lights. Just know that increasing the fuse could lead to buring something more expensive out.

[ted shred]

This may not address your problem directly, but it could be an alternative. If your truck has a factory tow package it may already have wire in the harness for aux back up lights. I know this is true of Chevy-GMC trucks & suvs. If you have one in there you can just hook into it and forego the other set up.

[DanC]

Assuming that you installed two 55 watt lights, the current draw should be less than 10 amps. Since your desribed the relay wiring, I am assuming you have no other loads on this circuit. Check your power wires to ground with an Ohm meter (take out the bulbs and fuse first) or start undoing connections until you isolate what is popping the fuse.