[AT] trailer lights

[Bill Herrmann]

At 11:57 AM 4/28/2004 -0500, Wayne Snelling wrote:
>To each his own. Keep in mind if you do run a ground wire from the vehicle 
>to a trailer lights connector, if anything goes wrong on the trailer 
>lights you blow the vehicle fuses, lights or even modules.

Um, that's what the fuses are for. If you're blowing anything other than 
the fuses the trailer wiring isn't properly fused. You're a lot more likely 
to blow modules etc. with phantom voltages caused by not running that 
ground wire.

>lights) and vehicle and if the trailer lights do a massive short then you 
>have a buffer.

That's what the fuses are for. Ideally each circuit that runs to the 
trailer should be individually fused. Most vehicles fuse them in a group, 
but it can be worth fusing them individually. As a bonus individual fuses 
make it pretty easy to know where to look for the problem -and- likely 
leave you enough lights to get home if it's not a field-fixable problem. 
(though most problems should be if you take at least a minimal tool set 
with you - Dad and I fixed an intermittent short in the trailer brakes in a 
campground at the top of the Canadian Rockies once - darned inconvenient 
when the trailer brakes suddenly go away... We were motivated to find and 
fix it permanently!)

No, my vehicles aren't all individually fused, but I'd probably make up an 
adapter with the fuses before using somebody else's trailer. With the 
individual fuses you definitely want to do a light check.

There is a reason that the trailer wiring you can buy comes in number of 
circuits plus 1. (and don't get me started on the idiot trailer 
manufacturer's that think it's so you can split the 4 wires in half and 
route them to the 2 sides of the trailer)

>  In fact, if you wire Chevy pickups in that manner you are sooner or 
> later going to blow the ABS module in them.

Having the ground through the trailer ball isn't going to protect the ABS. 
Having a fuse in the hot leads will.

Bill
'49 Farmall Cub