Hi, need a bit of help with my turn signal switch. I have a stock 1986 F250 7.3L Diesel. I KNOW, it is supposed to be a 6.9. but it was late 86 and somehow came with a 7.3. Anyway, after all of these years, my turn signal cam finally broke, (I live in Florida so the signals do not get used much) and I went to install the new one today. Done them before on my Bronco and F150, so figured it was no big deal, wrong. This is a completely different setup than the others. There is a three pin plug, triangular shaped rubber, that comes off the column side of the turn signal switch harness. It appears to be OEM. It goes to what looks to be a metal bodied relay of some sort that is under the dash, to the right of the gas pedal, and attached to the ABS module housing. There is an extra wire in the harness too. All seven ports along the top of the column side of the plug are full as well as all four on the bottom, usually it is only three on the bottom. I have never seen this set up before, can someone please fill me in and tell me how to modify my replacement switch or find the correct one? I am at a complete loss here.

Thanks.

 

First welcome to FTE

Now you say your truck should have a 6.9 but has a 7.3 motor.
You also said it is a late 86 truck and maybe why the 7.3?
What is the month/year on the cert sticker in the door jamb?
Does the truck have cruise control?
Any way to check out a 87 switch to see what it is like?
Dave ----

 

I have an 87, the switch is the same as the one replacement one I just bought. In fact I bought two because I had to replace the 87's last month. I have Ford trucks from 80 to 87 and this is the only one I have ever seen this configuration on. Can not even find it in the manuals, but it is stock OEM, no question about it.

 

7.3L swapped in, as it was introduced in 1988.

T/S switch: With or without a tilt wheel? Tilt wheel operates by pressing the T/S handle forward.

What year is this truck? Above you say it's a 1986, then in post #3, you say it a 1987.

1985/86 use the same T/S switches, 1987/89 is different.

 

No the 7.3 was not swapped in, it came that way. Should not have, but did. All my trucks have tilt wheels. I know there is a difference in the switches, but none come with that extra plug appendage, or show 11 wires.

 

How can a 1986 come with the 7.3L since it was introduced in 1988? Engine code is the 8th digit of the VIN .. post what it is.

 

In these diagrams, I see wiring is different for a Bronco, the f150-f350's are the same regardless of engine. I do see some wiring differences in the trucks if it has cruise or not.

Turn, Stop, & Hazard Lamps - ???Gary's Garagemahal

 

True Franklin2, there are some minor differences. And mine does have cruise control, it is the Lariat edition, extended cab. However I can find nothing to indicate a separate plug, coming off the turn signal switch plug. So I have no idea how to wire this. I have all of the Ford technical manuals, and can not find any reference to this set up.

 

I hate to disappoint you ND, BUT being the original owner I KNOW that the engine has NOT been replaced. Since the day I drove it home, the engine is marked as a 7.3 and is a 7.3. Checked that just to make sure it was not mis marked. I also have an 83 Jeep that I not only bought brand new, but had to order it and wait for delivery from Toledo, that has an engine configuration that was not supposed to be used until 1986.

 

You are not disappointing me, because I could care less.

The 7.3L info I gave you came straight from the 1980/89 Ford Light Truck Parts Catalog, but I didn't need to use it for reference, because I've known since 1988 that this was the year the 7.3L was introduced.

So...what is the 8th digit of the VIN? And while you're looking, what is the 10th digit of the VIN? Or post the entire 17 digit VIN

 

Post a picture of the Certification Label on the DS door jamb;

here is mine for reference:

 

On page 77 I see a separate plug. The plug for the turnsignal switch is C305. If you have cruise there is also a C305A.

If you look on page 78, in the list is says C305A illustration is located on page 139-2.

Turn, Stop, & Hazard Lamps - ???Gary's Garagemahal

Here is the link with the picture of C305 and C305A

Speed Control - ???Gary's Garagemahal Looks like there are two extra wires in the plug for the cruise signal wires.

 

Thank you Franklin2, I found that other plug the hard way. It is more of a short sub harness. The turn signal switch plugs into it, then it continues on and plugs into another plug similar to the turn signal switch plug with the 3 prong plug for the cruise control module coming out of it. Since I disassembled the plug thinking wrongly that I had to pull the wires through the steering column, I now have to rewire that lower plug, so that wiring diagram will be invaluable.