Blowing fuse when hauling a trailer

[TwistedCopper]

I just wired up a harness for a trailer, and when I haul it, the turn signal fuse blows after a while. The wiring is correct, and there is no contact to ground anywhere in the circuit. I believe that the extra lights are overworking my flasher and it is blowing the fuse. I say this because with the added load from the trailer lights the blinker blinks much more rapidly.

Possible?

I upped the fuse from 15A to 20A and it still does it. Can I upgrade the flasher? How?

[lah2420]

The flasher shouldn't blow the fuse unless the current draw is right at the blow point. All the flasher consists of is a strip of metal that heats up with current and pulls away from the contact that sends power to the light. When it cools, it drops back and makes contact. It wouldn't hurt to get a higher capacity flasher though to slow down the rate of flashing. I guess it is theoretically possible for the higher rate of flashing to pop the fuse since it takes more current to start a light than to just keep it lit. If you can find a 20 amp slow blow, you might try it too.

[TwistedCopper]

Originally Posted by lah2420

The flasher shouldn't blow the fuse unless the current draw is right at the blow point. All the flasher consists of is a strip of metal that heats up with current and pulls away from the contact that sends power to the light. When it cools, it drops back and makes contact. It wouldn't hurt to get a higher capacity flasher though to slow down the rate of flashing. I guess it is theoretically possible for the higher rate of flashing to pop the fuse since it takes more current to start a light than to just keep it lit. If you can find a 20 amp slow blow, you might try it too.

They're blade type fuses and I was thinking the flasher was heating up and causing more resistance, popping the fuse. I'm going to buy a new flasher first. It may be that the old one is just on the verge of it's death.

I really have no idea where else to start

[lah2420]

You're going the same route I would. Simple stuff first. I wasn't thinking on the type of fuses. I guess I still have old-school glass fuses in my brain.

One other thing that comes to mind from my days of chasing Ford light problems. Are you sure you have a good ground between the trailer and Jeep? I've seen light problems where the current finds a path through both filaments on the light back through the power source to the tail light. You might look at the light and see if both filaments light when the turn signal is on. Also, you might hook up a temporary wire from the trailer to the jeep frame.

[Craig]

You can upgrade your flasher which is what I had to do when I converted to LED tail lights. You should have an electrostatic flasher which the speed of the flasher depends on the amount of current being drawn through it. You can replace it with an electronic one which will have a constant flash speed. This should solve the problem of the lights blinking more rapidly and hopefully stop the fuses from blowing. It's only a $10 part.

[Bounty__Hunter]

You should be able to get a HD flasher that many have to upgrade to in order to pull a trailer.

[TwistedCopper]

Cool thanks guys... I'll try to get one in there soon

[dandoc]

LED lights will cause a flasher designed for filiment light bulbs to cycle quicker, making the lights blink faster. Like stated previously, an upgrade of the flasher unit will correct that problem. Is your trailer using all LED lights? Regardless, some flasher units are only designed to have the electrical load of 4 or 6 lights. Do your upgrade and you should be in the clear.

[TwistedCopper]

Bought a heavy-duty, or "loud" flasher and it solved the problem