SAAC Forum

The Cars => 1968 Shelby GT350/500/500KR => Topic started by: pied viper 041 on November 07, 2023, 08:29:29 PM

Title: temp. sending unit wiring question
Post by: pied viper 041 on November 07, 2023, 08:29:29 PM
My brown with white stripe s/u wire  broke off @ fire wall it was working fine until then. I cannot find where it goes back to. I think it goes to the plug where my ignition comes through the firewall to the coil  there is a red & black plug with two small wires coming from fire wall right above my a/c wire comes out .
Title: Re: temp. sending unit wiring question
Post by: Coralsnake on November 08, 2023, 06:49:55 AM
The temperature sender wiring lays on the intake. It is a red wire with a white tracer.

Title: Re: temp. sending unit wiring question
Post by: Coralsnake on November 08, 2023, 09:21:16 AM
A photo might be helpful
Title: Re: temp. sending unit wiring question
Post by: 68blk500c on November 08, 2023, 11:38:38 AM
Providing you with a photo which may be helpful.

At left is the white with red wire for the oil sender, which is scotch-lock spliced for length.
At right is lead (female) which your temp sending wire plugs into. WRONG INFO.  this lead is for the A/C compressor black wire.

CORRECTION:  Your temp sender wire is part of a taped loom that plugs into the triple connector which is pictured in the middle of these wires.
Title: Re: temp. sending unit wiring question
Post by: pied viper 041 on November 08, 2023, 12:05:29 PM
Pete I will try to send a picture. I took a few. Pete my sending unit wire is brown with white stripe. It is hooked up @ sending unit and stops @ fire wall it looks like it is broken off or cut where the wires comes through the fire wall . Where the ignition wire & the back up light wires comes through the fire wall. Maybe my wire is faded into brown .
Title: Re: temp. sending unit wiring question
Post by: Coralsnake on November 08, 2023, 12:15:16 PM
So far I dont recognize the wire
Title: Re: temp. sending unit wiring question
Post by: pied viper 041 on November 08, 2023, 12:37:29 PM
Thanks 68 blk I see my problem now. My sending unit wire broke off @ black/red plug. my plug is shot I will have to try something else.There are two wires red & yellow going to plug do you know if both wires go to sending unit.
Title: Re: temp. sending unit wiring question
Post by: 68blk500c on November 08, 2023, 07:39:52 PM
Single wire to temp sender, not two.
Title: Re: temp. sending unit wiring question
Post by: Bob Gaines on November 08, 2023, 07:49:35 PM
Plug in engine gauge feed harness has wires for the oil pressure ,temp sender and the coil.
Title: Re: temp. sending unit wiring question
Post by: 68blk500c on November 08, 2023, 09:15:12 PM
Quote from: pied viper 041 on November 08, 2023, 12:37:29 PM
Thanks 68 blk I see my problem now. My sending unit wire broke off @ black/red plug. my plug is shot I will have to try something else.There are two wires red & yellow going to plug do you know if both wires go to sending unit.

Guessing you don't have this illustration which shows the colors for your three wires----read lower right for A, B, C wire colors.  Beginning to sound like you need a replacement loom segment for this triple plug. 

In an assembled car it is tricky to try to determine which wire goes to what position of the triple plug.  Maybe someone else can confirm this?
Title: Re: temp. sending unit wiring question
Post by: J_Speegle on November 08, 2023, 10:03:12 PM
Quote from: 68blk500c on November 08, 2023, 09:15:12 PM
Guessing you don't have this illustration which shows the colors for your three wires----read lower right for A, B, C wire colors.  Beginning to sound like you need a replacement loom segment for this triple plug. 

Believe those colors identified are on the main loom (attached to the black plug) not the engine feed one.

Believe we will find that the engine feed coding and arrangement will differ depending on engine type and possibly even production period but haven't tested that last one  ::)


Examples of four engine feed loom connections. Notice the position of the black wire and the lack of a black wire in some


(https://www.concoursmustang.com/forum/gallery/19/6-081123220233-197541834.jpeg)



Title: Re: temp. sending unit wiring question
Post by: 68blk500c on November 09, 2023, 10:26:32 AM
Prompted by Jeff's input, I double-checked the '68 Electrical Assembly Manual and both big block and small block show to be the same wire color scheme for this engine harness.
Title: Re: temp. sending unit wiring question
Post by: J_Speegle on November 09, 2023, 05:09:35 PM
The challenge I find with the pages chosen by Jim that make up the  reprints of the Assembly manuals is that we don't know why a particular page was printed, what the details were before it was published and sent out to the car plants and when (if they were) each page was redone to reflect a change or a mistake on the distributed page in the manual. Just my concern about the details contained within.

As for the examples I posted it appears that the color codes of wire may have changed during production. Example: In the picture I posted the

- Upper left is from a 6 cylinder with the black wire in the end of the plug

- Lower left is from an early GT350 with the black wire in the center point of the plug (Approx late November build) Have other examples of early built C and J codes with the same configuration

- The two plugs on the right that appear to match with a white with red tracers are from C & J code Mustangs built during December and later

(https://www.concoursmustang.com/forum/gallery/19/6-081123220233-197541834.jpeg)


With that all said and the pictures identified by application I found that early small block cars had a different engine feed loom that later cars as illustrated in the picture above. Early with the black with and the later with the white with red tracer in the center position.

For those that attended this last years SAAC National event the lower left example was from that very nice unrestored blue GT350 that was in the parking area that allot of us were looking at and taking pictures of
Title: Re: temp. sending unit wiring question
Post by: pied viper 041 on November 27, 2023, 11:38:46 PM
Thanks for the help to all. I had to pull my instrument cluster assy. out and follow the temp. gauge wiring to the the plug that goes to my firewall . I had a broken wire going through my firewall The plug going through my firewall was some kind of a serious grommet I had to go through the hole where my oil guage going to my console wire goes. red wire goes to temp guage yellow wire goes to oil light on dash coming out of wires going to red & black plug. It works fine now thanks again .    James