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Kenrbass · 10-01-2021, 04:55 PM

This system seem so basic, yet it will not work. Old holiday rambler has separate blinkers and brake lights on the rear, like an import vehicle. I bought two different convertors for 3 wire, to 2 wire (brake and blinker shared on trailer) Neither one work. I am a retired ase master auto tech with electronics training. I can't figure out why neither the curt 56130 or the tekonsha 119178 will function with a test light test on the back. Blinkers pass through and tail light, but brake lights fail to pass through on both convertors I tried.

I have resorted to ordering some relays, transistors, capacitors, resistors, and will build my own. I'm sure I can be the only trained idiot that can't make a simple light covertor work.

5 wires feed in and 4 feed out.

Has anyone fought this battle and won?

Thanks

Skip426 · 10-01-2021, 06:33 PM

After 33+ years of automotive electrical , I admire your dedication to making the stock system work .

Myself , I'd have converted the trailer to a single bulb each side, system by now .

kdauto · 10-01-2021, 06:35 PM

Since I am unfamiliar with your Holiday Rambler, I'll tell you why this fails on most modern vehicles.

When I do an install I am generally using a converter that runs a separate bigger gauge (usually 14ga or 16ga) wire to the battery. Modern vehicles use small wires to power taillights. Many are computer controlled, many are LED and the small wires or body computers won't push the amps needed for any incandescent lamps added on (the trailer or toad).

Make sure your converter ground is on clean bare metal and that it is hooked up before you power the converter up.

SteveJ. · 10-01-2021, 07:16 PM

Quote:

Originally Posted by Kenrbass

This system seem so basic, yet it will not work. Old holiday rambler has separate blinkers and brake lights on the rear, like an import vehicle. I bought two different convertors for 3 wire, to 2 wire (brake and blinker shared on trailer) Neither one work. I am a retired ase master auto tech with electronics training. I can't figure out why neither the curt 56130 or the tekonsha 119178 will function with a test light test on the back. Blinkers pass through and tail light, but brake lights fail to pass through on both convertors I tried.

I have resorted to ordering some relays, transistors, capacitors, resistors, and will build my own. I'm sure I can be the only trained idiot that can't make a simple light covertor work.

5 wires feed in and 4 feed out.

Has anyone fought this battle and won?

Thanks

You could try a powered isolator/combiner. Curt 56236 or similar. This will isolate the trailer wiring from the TV wiring.

Kenrbass · 10-02-2021, 08:23 AM

I have parts ordered. A few relays, transistors, capacitors, and resistors will do the trick. I am passing the brake signal through to the NC contacts of two relays. The relays will be energized by the turn signal with a delay off (about 3 seconds) so the relay will stay on until the next flash.

It does not have led lights and I am just checking the connection plug with a small bulb test light. Even without a trailer, the brake light will not pass through either convertor.

I did contemplate adding extra lights to a trailer, but I will pull several different ones.

cfowler55 · 10-02-2021, 10:07 AM

Have you tried actually plugging in to the trailer? I’ve installed some converters that require more of a load than a test light will provide to function. And I agree that the battery powered converters tend to work better. I also retired in June after 48 years in auto repair. Nice to have clean fingernails. Ha.
Charlie

Toby Dog · 10-04-2021, 04:13 AM

I had to get one of these once to get a trailer home. Extra length had to be spliced in. Just a thought but admire your diag etc.

https://www.amazon.com/MaxxHaul-8077...a-537017216051