All taillights flash with blinker when headlights on

[Zackie]

Okay so, the other day I made a post about my 01 sporty having all the taillights flash with the blinker, at first putting a new multi-function switch worked to fix the problem, unfortunately it’s back and seems to be a problem with the wiring, I’ve replaced the end connection before as the wires tore out of the original connection, Can anyone tell me how hard it would be to swap out the harness for a old one from a junker? At this point I wanna put in a harness that hasn’t been messed with and see if it fixes this issue

 

[Rick]

It's not a fun job to remove a harness since so much has to be removed to get it all out. Have you checked all of the bulb sockets for corrosion? Bad grounds can cause strange issues like this.

 

[410Fortune]

I second checking the bulbs themselves and the bulb sockets
Sounds like you have a short circuit which could just be a bad bulb or bad connections at a tail light or turn signal light or parking lamp bulb

So you replaced the pigtail leading into the multi function switch, is there more damaged wiring there?

 

[Zackie]

I second checking the bulbs themselves and the bulb sockets
Sounds like you have a short circuit which could just be a bad bulb or bad connections at a tail light or turn signal light or parking lamp bulb

So you replaced the pigtail leading into the multi function switch, is there more damaged wiring there?

Bulbs and sockets are brand new, I’ve checked them, I figured out it’s the harness by checking the wires, I went and messed with them a little and it fixed it again before it went back to all of them flashing again

 

[410Fortune]

Where?
At the multi function switch?

Fix the harness you have is way easier than swapping in a new one…. Maybe depending on where the issue is
Most of the steering column wiring is very short, it plugs into the truck right under the column. So if your issue is in the steering column harness you can replace it quite easily
But you just be careful here those multi function switches and the wiring to them changed quite often

 

[Zackie]

Where?
At the multi function switch?

Fix the harness you have is way easier than swapping in a new one…. Maybe depending on where the issue is
Most of the steering column wiring is very short, it plugs into the truck right under the column. So if your issue is in the steering column harness you can replace it quite easily
But you just be careful here those multi function switches and the wiring to them changed quite often

That is also true, it’s at both ends unfortunstely that’s why I’d rather replace the harness, im trying to find one out of a 01 Sporty Base Model like mine if I do go that route, I might just take both ends and spline them in though as well after doing some preventive maintence so the wires don’t get ripped out

 

[429CJ-3X2]

On my '01 Sport Trac, the problem wasn't that the wiring was too short, but that it was taped to the column so the slack was at the bottom instead of the top where it's needed. I carefully cut the tape holding the harness to the column and retaped it so the slack was at the top after I fixed the wires that had pulled out. I think some of the connections in the connector that plugs into the multifunction switch had pulled out, so I got a connector at the salvage yard to replace it. I cut the harness on the salvage yard connector so that I had a length of each wire going into the connector still attached so I could replace them with the correct wire one at a time when I hooked it up to the truck's harness. Hope that makes sense. It's tedious, but not difficult.

 

[Zackie]

On my '01 Sport Trac, the problem wasn't that the wiring was too short, but that it was taped to the column so the slack was at the bottom instead of the top where it's needed. I carefully cut the tape holding the harness to the column and retaped it so the slack was at the top after I fixed the wires that had pulled out. I think some of the connections in the connector that plugs into the multifunction switch had pulled out, so I got a connector at the salvage yard to replace it. I cut the harness on the salvage yard connector so that I had a length of each wire going into the connector still attached so I could replace them with the correct wire one at a time when I hooked it up to the truck's harness. Hope that makes sense. It's tedious, but not difficult.

This makes sense, just gonna be tedious to do like you said, This would most likely be my last way of attempting to fix it

 

[Zackie]

Update: Problem became worse today, Now I have no taillights blinkers and my wiperblades got stuck on at max

 

[410Fortune]

Multifunction switch and the wiring too it, this is the only Place where lights and wipers meet

Do you have your old multi function switch?

Take the shrouds off the steering column and start wiggling wires. Try the tilt wheel feature a few times see if it has any effect

Sounds like it has gotten worse
It is time for a visual inspection of steering column wiring and behind the knee guard

 

[Zackie]

Multifunction switch and the wiring too it, this is the only Place where lights and wipers meet

Do you have your old multi function switch?

Take the shrouds off the steering column and start wiggling wires. Try the tilt wheel feature a few times see if it has any effect

Sounds like it has gotten worse
It is time for a visual inspection of steering column wiring and behind the knee guard

I've done three switches on it now, All three of them do it, I've gone back and forth with them all, But now its gonna go on the backburner as my rear end blew.