Decent FJ40 trailer wire connect method (1 Viewer)

[SteveH]

I would like to put a 4-flat trailer connector on my 1980 FJ40. Someone did the past with tap-a-lines in the usual hackneyed way and I have repaired the harness.

Has anyone ever found a decent/robust way to connect trailer wiring on an FJ40?

thanks - Steve

 

[Fast Eddy]

For towing a trailer or for towing your 40 as a trailer?

For towing my 40 I have a completely separate harness that goes from a trailer plug under the front bumper to some small LEDs by the tail lights.

I haven't done it, but my favorite way for towing a small trailer would be to get two sets of male and female connectors for the tail lights and make a harness that inserts at that harness joint, so it could easily be removed and you wouldn't have to modify your wiring harness at all.

 

[SteveH]

Your harness mod suggestion is great, but finding OEM 1980 FJ40 taillight connectors seems difficult - unless there's an aftermarket source (?)

FYI - I want to tow with my '40 - I don't want to tow my '40.

 

[antFJ]

the PO had done those splice connectors that just go around the factory wire.. i didn't want to mess with them when i went through the harness so i left them. I wrapped them up good to keep them water tight and recently just got my trailer wiring hooked up.

you will need a 3 wire to 2 wire converter
Tail Light Converters

and this is what i attached to the rear of the bumper using factor holes...
Replacement Multi-Tow 6-Way and 4-Way Trailer Connector Hopkins Custom Fit Vehicle Wiring 40965

for this part i cut of the tail end of it and spliced it into the converter

my butt conectors were heat shrink wrapped which i bought from Fastenal - the two items above i bought from autozone

 

[SteveH]

Thanks - all good advice. I just used one of those multi-sockets on my F350, and they are cool.

What I find hilarious is that the PO tapped into three wires for the 4-flat connector - the parking lights, the brake lights, and the right turn signal. Odd way to wire up your trailer lights! I guess I should be thankful that he didn't butcher it all, as most do.

 

[Living in the Past]

74 and up needs a adapter since the brake light and turn signal use separate lamps. On a four pin those would be a share a element in the dual element lamp. Modern vehicles (or at least modern Toyota trucks) use a box to covert to a four pin. But the factory light wiring only power a relay and the power for the trailer lights comes from it's own fused source. Not only will this keep the load down on the old factory wiring, the flasher will not blink faster under a heavier load.

 

[SteveH]

I'm familiar with the powered and non-powered 5-4 wire converters - but thanks for mentioning it. The powered converters add some juice back to the system to keep the trailer lights brighter, but require a 12v feed to operate.

Steve

 

[subzali]

For towing a trailer or for towing your 40 as a trailer?

For towing my 40 I have a completely separate harness that goes from a trailer plug under the front bumper to some small LEDs by the tail lights.

I haven't done it, but my favorite way for towing a small trailer would be to get two sets of male and female connectors for the tail lights and make a harness that inserts at that harness joint, so it could easily be removed and you wouldn't have to modify your wiring harness at all.

Wouldn't this give you only lights on your trailer, or is it a parallel plug-in so that your body lights still work?

 

[seapotato]

I need to deal with this in the next little while too. Added bonus is my truck being 24v...( sarcasm on) but that's a separate issue...


My thought to this point was to pop out the tail light housings ( recently bought new ones ) and tie into the tail light pig tails, AFTER the plugs from the factory rear wiring harness.

I figger this way the wire is newer , ie, not black and crappy like the rear harnesses usually are so it should make a better contact, and it's removeable , so I can do the wiring while sitting at my bench sipping a beer, instead of lying under my truck with s*** falling in my eyes.

also could be moved to another truck

I'm delaying on this tho in the hopes there's a better solution out there, but so far I'm liking this one.

cheers,

Ryan

 

[SteveH]

Uhaul (only Uhaul) sells the pigtail-equipped turn and brake light bulbs. Mail order only - not sold at Uhaul dealers. I have considered using these to make a non-invasive attachment method. Won't work worth a hoot on a 24V system....

U-Haul: Moving supplies: Tap-A-Lite

I like the idea of tapping into the taillight fixture itself to get a cleaner connection point.

 

[Living in the Past]

I have a very original 76 and it has a plug in the tail light loom right in the center of the back. Not sure how many years had this or if this was a option but it looks stock. Don't remember ever seeing another one before. But it is shown in factory wiring diagrams.

 

[SteveH]

The center back section of my 1980 harness has a 2-lead plug - one is taillights (not brake) and the other is a ground. Nice, but not enough for towing.

 

[Living in the Past]

The center back section of my 1980 harness has a 2-lead plug - one is taillights (not brake) and the other is a ground. Nice, but not enough for towing.

Mine might be four wire but that's still not enough on a post 73 unless it have a converter from separate brake/turn single to a single bulb which I'm sure it doesn't have. The very early land Cruisers had a military style trailer light jack. It has four blades inside and only used three. Need to look at the early wiring diagrams to see if they are missing the ground or what.

Edit: just found the FJ25 wiring diagram and it shows ground/brake lght/tail light for the three wires. But the wiring diagram is not what the US market got. Shows turn signals on the each side and a single brake/tail light in the center. Need to look at my 62 FSM and see if it shows anything better.

 

[AlaskanWheeler]

One thing you could posibly do is splice in a weather pack connector, and run the pig tail wires into a nice five pin connector mounted to the rear bumper.

Weather Pack Connector Kits Megasquirt Kits / Assembled Engine Management Systems, Wideband o2 Sensor Systems and tuning products - DIYAutoTune.com


TAP 5-Pole Round Car End Trailer Connector | Adapters | Northern Tool + Equipment

 

[Tennessee80]

the PO had done those splice connectors that just go around the factory wire.. i didn't want to mess with them when i went through the harness so i left them. I wrapped them up good to keep them water tight and recently just got my trailer wiring hooked up.

you will need a 3 wire to 2 wire converter
Tail Light Converters

and this is what i attached to the rear of the bumper using factor holes...
Replacement Multi-Tow 6-Way and 4-Way Trailer Connector Hopkins Custom Fit Vehicle Wiring 40965

for this part i cut of the tail end of it and spliced it into the converter

my butt conectors were heat shrink wrapped which i bought from Fastenal - the two items above i bought from autozone

Thanks for this info, I was stumped! Just ordered the 3 wire to2 wire converter for my 40.... Cheers, Joel

 

[Tennessee80]

the PO had done those splice connectors that just go around the factory wire.. i didn't want to mess with them when i went through the harness so i left them. I wrapped them up good to keep them water tight and recently just got my trailer wiring hooked up.

you will need a 3 wire to 2 wire converter
Tail Light Converters

and this is what i attached to the rear of the bumper using factor holes...
Replacement Multi-Tow 6-Way and 4-Way Trailer Connector Hopkins Custom Fit Vehicle Wiring 40965

for this part i cut of the tail end of it and spliced it into the converter

my butt conectors were heat shrink wrapped which i bought from Fastenal - the two items above i bought from autozone

Thanks for this info, I was stumped! Just ordered the 3 wire to2 wire converter for my 40.... Cheers, Joel

 

[AUMike99]

I have a very original 76 and it has a plug in the tail light loom right in the center of the back. Not sure how many years had this or if this was a option but it looks stock. Don't remember ever seeing another one before. But it is shown in factory wiring diagrams.

I have this as well... do you know what it is for? thanks!

 

[AUMike99]

The center back section of my 1980 harness has a 2-lead plug - one is taillights (not brake) and the other is a ground. Nice, but not enough for towing.

I have this as well. What do you believe this would have been used for? Mounting a light of some sort? thanks!

 

[Braden620]

I have the wiring as well. Assumed it was for trailer lights but never probed it with a multimeter.

 

[DenverMike]

Thanks for this info, I was stumped! Just ordered the 3 wire to2 wire converter for my 40.... Cheers, Joel

Did everything work out for you? I’m only trying to get wiring so I can plug in an external tow light set up to put on my bike rack so people can clearly see my lights when I’m breaking or turning (and driving at night.). I went to U-Haul today and the guy assured me it would be a simple install an hour and a half later he had somehow managed to melt my brake light relay switch and only get the running lights and turn signals working.
here’s a pic of my funny little connector that Uhaul bypassed entirely - and a pic of my melted switch.