73 Gmc wiring help needed with pics/fuel,temp,3 green wires

[73GMC10]

Hello, i have a question, actually i have 3 i will try make them simple so its not so jumbled. i aquired this 73 gmc custom and have some mystery wires that im not sure where they go,i tried to look it up for a while now and cannot seem to understand where i need to hook them up so i thought i would come here for some help.i posted 2 pics of the wiring at the drivers fire wall box and the 2nd is 3 green with a yellow mystery wire,this truck has no a/c and never had installed.

*the wires labeled in red 1 and 2 are not plugged into anything, when i tried either wire nothing worked for the fuel or temp,but that doesnt mean they arent the right wire im just asking so i get the wiring right at least.

1.my fuel gauge wire it is one single wire that runs from the tank but stops by the brake booster meaning its been cut.

2.my Temp sending wire is also cut at the brake booster.

3 that cluster of 3 green wires with one yellow is cut and taped in the middle of the fire wall above the distributor. i have not found any place they connect as the green wires for the brake lights/tail lights are ran separatly down the driver side.and it does not and never had any a/c installed on it.

i appreciate any help or insight i thought perhaps the pictures of the firewall box might help to point me in the right direction. thanks for looking.
*edit one of those 2 wires in number 1 that are labeled in red 1 and 2 is a live 12 volts incase it helps any**

[chengny]

Originally Posted by 73GMC10

Hello, i have a question, actually i have 3 i will try make them simple so its not so jumbled. i aquired this 73 gmc custom and have some mystery wires that im not sure where they go,i tried to look it up for a while now and cannot seem to understand where i need to hook them up so i thought i would come here for some help.i posted 2 pics of the wiring at the drivers fire wall box and the 2nd is 3 green with a yellow mystery wire,this truck has no a/c and never had installed.

*the wires labeled in red 1 and 2 are not plugged into anything, when i tried either wire nothing worked for the fuel or temp,but that doesnt mean they arent the right wire im just asking so i get the wiring right at least.

1.my fuel gauge wire it is one single wire that runs from the tank but stops by the brake booster meaning its been cut.

2.my Temp sending wire is also cut at the brake booster.

3 that cluster of 3 green wires with one yellow is cut and taped in the middle of the fire wall above the distributor. i have not found any place they connect as the green wires for the brake lights/tail lights are ran separatly down the driver side.and it does not and never had any a/c installed on it.

i appreciate any help or insight i thought perhaps the pictures of the firewall box might help to point me in the right direction. thanks for looking.
*edit one of those 2 wires in number 1 that are labeled in red 1 and 2 is a live 12 volts incase it helps any**

I have the wiring diagrams and will try to help you but - if you read your post carefully - you'll notice that it contains no questions that we can answer. It is just several statements describing the condition of your wiring.

For example, are you asking which wires coming out of the bulkhead connector should be connected to the cut leads (for the fuel tank sender and coolant temperature sender)?

If so, they need to be connected as follows (these are both in the far LH column of the engine section of the connector - indicated by the arrow):



1. Coolant temperature sender/switch to the DK GRN wire in the 2nd bay from the top.

2. Fuel tank sender lead goes to the TAN wire in the very bottom bay

On the wires shown in the second image:

Are you sure that isn't part of your rear lighting harness? I'm so color deficient that I'm almost color blind, so I can't tell. But is it possible that the lead indicated by the arrow might be brown? If so, those four colors would be exactly the same as the LT GRN, DK GRN, YEL & BRN that comprise the rear lighting harness.



The way the wiring dwg reads, all the rear lighting leads transit the bulkhead connector in the RH block - in various bays. They run a short distance in the engine compartment and then they are all grouped together into a plug that mates with a socket. After exiting the socket, they all head back to the rear lighting assemblies. Also, the only YEL wire that passes through the firewall is for the LH directional/brake light.

What is the color/quantity of the leads on the LH side of the wiring clip (in the circled area)?



It looks like there are more on the RH side of the clip than on the LH side.

Do you have a 4-speed manual transmission?

[hatzie]

Is this an AC equipped truck?

[73GMC10]

Thank you for responding to my topic, i will try the green and tan wires for the temp/fuel guages.

it is a sm465 tranny with granny low, never had ac equipped in it

as for image number 2 where you circled it in yellow that taped off section is where it ends as the wires are cut off there kinda in the middle of the engine bay without any other green wires to be found around the engine but i suspect one of the green wires could be the temp sensor lead, as for the other 2 green wires, its a mystery as yes i have a totally separate set of green wires going down the driver firewall side to the rear lights and when i crawled underneath to look there was nothing cut or altered and my rear lights work,so im wondering if the remaining 2 green and 1 yellow can just be capped off as i dont see any other use i could need them for,unless could they go to the tranny for a reverse light? just thinking as im not really knowledged in how the standards and reverse light work

****EDIT*** i made some headway, thinking the tranny had to have wires coming from it i crawled underneath and sure enough way up they are snipped off 2 green ones, and it leaves 1 green (dark) wire left so that must be my temp wire.. only one now is the yellow and as everything else seems to work and the blower motor work i could probably cap it off i think