Wire identification help (1 Viewer)

[78GroundUp]

OFF got two wires I can't seem to identify. Done pretty well with everything else. Thanks to y'all.

Wire on left is riding in main rear harness. Just hanging out there.

The wire on the right is coming of the "finger" or "splice" leading up to reverse light connection, seatbelt, fuel sender, etc........

They both appear to have 30 years worth of mud, dirt, debris. When I bought the truck it did not have a rear heater at the time. Makes me wonder if it's heater related? That said, they are also far enough apart that they might not be related at all....

I have looked at many different wiring schematics. I conclude I am not smart enough to figure those out, or this wiring dilemma.

Thanks ahead of time.

 

[grant5127]

What's the wire colors?

 

[78GroundUp]

Left: is blue and red- for sure. Right: is Blue / or maybe blue and red... not sure?

 

[thecrazygreek]

Blue and red is your back up light wire.. so thats easy, the other may be your vss (vehicle speed sensor) wire going back to emmision "computer"...

 

[donny paradise]

the other may be your vss (vehicle speed sensor) wire going back to emmision "computer"...

Boy, that was a shot in the dark, but a miss . Funny tho.

 

[mikeob1]

4x4 indicator light coming from transfer case?

 

[spotcruiser]

Yep, I'd say the forward wire is an unused transfer indicator wire and the after one is a reverse switch wire. I've never seen a transfer indicator, as far as I know, but I believe my '78 has that wire also. The indicator is probably necessary if you have a vacuum shifter mechanism. I wonder if some non-US models still had the vacuum shifter in '78.

 

[grant5127]

US trucks around '78 era had a transmission position switch that had a blue or blue with yellow stripe wire.... sent a signal to the emission control center computer....

 

[thecrazygreek]

If there both Blue and red, then (methinks) the other is the seatbelt warning relay wire. Same color as the BU switch wire.

 

[thecrazygreek]

Boy, that was a shot in the dark, but a miss . Funny tho.

Wait a second.. I just read your post.. what exactly is the funny part?

There IS a blue wire in that area that goes to the emmisions computer on a 78 rig... I dont get the "shot in the dark" comment...

Am I missing something?

 

[spotcruiser]

Yep, now I see that on my wiring diagram.

US trucks around '78 era had a transmission position switch that had a blue or blue with yellow stripe wire.... sent a signal to the emission control center computer....

 

[78GroundUp]

With above info I should add. Reverse switch is plugged and working. As is the seatbelt indicator, and fuel sending unit. There is a transmission sensor on top of tranny. And that wire was plugged in appropriately.

So these two wires seem to be to nothing?? (for now). (I repeat myself) this truck did not have a rear heater when I got it in '91. A fellow mudder gave me the entire setup for a great price. So I am now trying to figure out wires/switches/indicators for the heater setup.

I believe the sensor on top of tranny. With green plug is a 4wheel drive indicator. Need to get the indicator light for dash. Necessary no, do I desire having it, yes.

Basically: all things plugged in but heater and those two wires still hang free.

Was there a passenger seat, seat belt indicator at some time? Or maybe these are heater wires.

I am on my phone so can't read responses... But am confused by the emissions computer statement..... What an where is that?

"Keep shooting ideas or arguing about it.... It spurrs me to research different possibilities."

Thank you for the help.

EDIT: here is the book I am using. Seems to not have the 78 wiring in it.

78 FJ40 (except USA & Canada)
FJ40 for (USA and Canada) starts in 79???



Turn the page......



...... This is the diagram - note: headline

Confused?? Wrong book?

 

[Fuzzy Logic]

The heater wires run down from under the dash panel behind the ash tray and travel along the heater hoses to the rear heater. No passenger warning belt indicator.

 

[78GroundUp]

The heater wires run down from under the dash panel behind the ash tray and travel along the heater hoses to the rear heater. No passenger warning belt indicator.

Thanks fuzzy, so not in harness. This helps. Eliminates rear heater possibilities....

Also when looking in Toyota: Chassis/Body. I can't find a four speed tranny with the sensor on top. Not the reverse light switch. This is a second sensor. I believe (????) it's the four wheel drive indicator switch. But no idiot light on dash, never has had one that i know of...... So, Anybody got one??

 

[Fuzzy Logic]

The 4X4 indicator switch would have to be on the transfer case, see one? I don't think so.

 

[78GroundUp]

The 4X4 indicator switch would have to be on the transfer case, see one? I don't think so.

Nope not on transfer..... So I get.... Although this is off topic from my original thread it is part of the problem solving equation ..... If this is an indicator sensor(?) where/what does it indicate? Etc.... 5/78 - FJ40

 

[donny paradise]

Your transfer case shifter lockout is missing. Bad JUJU could happen if someone got a little careless while off roading.

 

[78GroundUp]

Your transfer case shifter lockout is missing. Bad JUJU could happen if someone got a little careless while off roading.

Old pic when in garage.... It's there now. Thanks for the heads up.
Donny, you got any ideas on the two wires or the extra sensor? Not the reverse light switch but the other with green connector?

 

[platypusREX]

Ah Grass Hopper! , that is the transmission position switch. It goes directly to the emission control computer. You can find it in your schematic if you locate the ECC. It is right under it. I will try to post the schem. in a couple of minutes.

 

[platypusREX]

Follow the location of the photo and you can DL a big version.

This is from the Haynes manual. Get one, I just found out right now that they arent too bad.