When I got my truck, there were 4 lights in the rear. Two turn signal lights and two brake lights. I removed them and taillights from midfifty. The issue I am having is that when I put either turn signal on, all the lights flash (like the hazards are on). Also, when braking, all the lights light up including the front turn signal indicators and this also overrides the turn signals from flashing when braking.

I must be doing something wrong. The headlights and running taillights work fine. The issue comes in when either braking or using the turn signals. Please help. Could it be the old style turn signal unit I am using is meant to be run with 4 taillights instead of 2?

 

Are you working with a wiring diagram for the signal unit? If not, google Signal Stat or search this forum for one to use. The issue for combining tail lights is with sockets and bulbs initially. The wiring needs to respect the circuit paths. Not rocket science.

 

Normally the brake, signal and flasher are all the same wire. Did you have tail lights before?
Sounds like you may have crossed the wires. If I remember correctly there are only 3 wires - ground, brake and tail. If they are crossed the brake lights will come on with the signal.

 

That is most likely your problem exactly. Many add on turn signal kits were not designed to integrate with the stock wiring. They were set up as a stand alone setup. That's why they had separate lamps. Your choices would be to reinstall separate lamps again, or swap out the signal switch with one designed to work with the brake lights, too. Commonly they are known as 4 wire or 7 wire switches, depending on if they're integrated systems or not. I'm guessing you have a 4 wire switch.

 

I'll save you searching for the MANY threads on this topic... Your old system was like the 902/903 (4-wire system), now you have a 900/901 (7-wire system) type of switch.

Undoubtedly your brake lights are on the same circuit from the previous set up. Now they need to be on separate circuits, fed by the turn signal switch.

 

My truck only had brake lights so when I rewired the entire truck I installed directionals. I've attached a copy of the wiring diagram that came with mine and my headlight wiring diagram. I have a 12 volt (negative ground) electrical system in my truck and I'm not positive what yours is but I hope this helps you.

Thanks,

Wally

 

... I had the same problem but with the original number of lights. After you verify the wiring against the diagram, inspect every inch of the wiring from the rear wheels back... I found around 8 of those old taps that U-Haul used to hammer into the wiring when someone rented a trailer and most of them were thoroughly corroded. With one or two, it's easy to insulate them, I just wound up re-running all of the wiring in the back. Never had another problem, after that.

 

My truck did not come with factory installed turnsignals. At some point to comply with PA State inspection my grandfather put a signal stat turn signal unit in. So the truck had turnsignal lights (red and amber) on top of the front fenders and separate turn signal lights at the rear. When I rebuilt the truck in 1999 I put dual filament bulbs and sockets on the front parking lights to eliminate the signals on the fenders and wanted to only have one pair of lights at the rear for tail, brake and turn.

try as I might I could not accomplish it and time was running out as I had to get it inspected so I put on the old rear turnsignals that were on before. Now I like having a separate turnsignal at the rear. I think it is important to have separate turn signals to better warn tailgaters of your intentions. I always fear a rearend collision with an occupied driver!

A few years ago I found a good used Grote turnsignal light to match my other one and added a new lens to the old one to clean up my rear lights. Here is a pic of what it looks like now:

 

Jim -

Do you solve your tail light problem?

DW