First time towing and having brake light problems!

[Oscar]

I just bought myself all the necessary towing parts to tow a brand old tent trailer. Got her all hooked up and the rear lights and brake lights on the trailer would not turn on at all. We tested the lights with the GMC Safari that towed it for years and they functioned fine. When I had it connected to my 4runner, the side lights would work but not the brake lights. Here is the connection I used:

4 pin in trailer to 4 to 7 pin adaptor to 7 pin connector in 4runner.

I've never towed a trailer before so any suggestions you have are much appreciated.

 

[Spider5]

I would start troubleshooting at the 4 pin adapter you attached to the Runner. Using a voltmeter, are an easier way, go to a car part store and buy a plug with some LED's that lights up each function, and check each pin on the connector. From past experiences you will likely find that the wiring on the trailer is not correct. Likely the other truck (GMC ???) had the hitch wiring done by an amatuer and they matched the trailer to make it work not following the standard pin-out protocol.:bash:

 

[Oscar]

Thanks for the input. That is a definite possibility. I'll check it out.

 

[don_lapre]

i had that same problem too. and trouble shot it to the little black box (backlight trailer circuit thingy). since i was too cheap to have that replaced ($180 from dealership) i just took it out (so i bypassed it.) now every trailer works, boat, camper, etc. The only thing that's been causing problems is hauling a heavy boat and my lcd screen often fades or dims when i brake. kinda weird cuz it doesn't happen with a light tow.

 

[Spider5]

i had that same problem too. and trouble shot it to the little black box (backlight trailer circuit thingy). since i was too cheap to have that replaced ($180 from dealership) i just took it out (so i bypassed it.) now every trailer works, boat, camper, etc. The only thing that's been causing problems is hauling a heavy boat and my lcd screen often fades or dims when i brake. kinda weird cuz it doesn't happen with a light tow.

What year is the 4Runner you are talking about

 

[Cleric]

What year is the 4Runner you are talking about

based on his signature, I would assume 2000.

 

[Spider5]

based on his signature, I would assume 2000.

The reason I asked to double check is because if it is a 2000 he is trying to compare a problem of a 2000 with a 2003 totally different animals regarding electrical towing connectors.

 

[Leebo]

For what it's worth, I went through a similar problem about a year ago. The factory 4 pin tail light converter "thingy" apparently crapped out before I ever had a chance to put it in use. I have a '99 4Runner btw.

I have run into this sort of problem on other vehicles but they were all aftermarket converters. I was amazed to find that the factory-quality converter died (and again, it was never put to use). I picked up a 4 pin converter at my local Walmart (for under $20) and wired it in place of the OEM unit. Problem solved.

I also added in a 7 pin connector for trailers with electric brakes and accessories, and installed a brake controller all at the same time. Walmart also had a decent replacement 4 pin and 7 pin combo connector that I installed in place of my factory 4 pin connector. Bolted up in the factory mounting holes for the 4 pin connector.

 

[Koz]

I would start troubleshooting at the 4 pin adapter you attached to the Runner. Using a voltmeter, are an easier way, go to a car part store and buy a plug with some LED's that lights up each function, and check each pin on the connector. From past experiences you will likely find that the wiring on the trailer is not correct. Likely the other truck (GMC ???) had the hitch wiring done by an amatuer and they matched the trailer to make it work not following the standard pin-out protocol.:bash:

:iagree:

Koz