I just bought a pop up camper to tow with my 99 4runner. It has a 7 blade rv plug with brakes. I have a 4 flat plug. I bought a 4 to 7 adapter "realizing I would not have trailer brakes " I just wanted to get it home a short distance. I hooked it up and only running lights worked.
My 4runner got a burnt electric smell inside so I unplugged it right away. Both trailer and truck work well when hooked up to other vehicles/ trailers. Any thoughts why it would smell burnt like that. I don't want to fry anything. Thanks for looking Jesse

 

Presuming the trailer lights themselves are not the cause of the issue, I would check the 4 pin connection at the back of your Runner.

The test light adapter that simply pushes in to the 4 pin is about $5-10.

From there if you discover the 4 pin signal is faulty then look into the 'little black box" on a 99 it is on the drivers side rear cargo area inside the back corner of the truck-you have to pull the cargo area trim pieces.

You can look up some of my other postings if you need more info on the black box, but check your output before you go to all that trouble.Pics on my Facebook pages.

 

Thanks so much. Didn't know about the black box. I'll check connections again and then the box if neccesary. I need to add a brake control as well so I'm in for a learning experience.

 

glad to help Jesse.

 

Thanks. It was a bad converter box. I bought a replacement one at AutoZone locally for 14.99 .
Hopkins 48845 hope that solves it.