Under Dash Wiring Mystery

[Matt69olds]

PROGRESS - Thanks to you guys I was able to get cargo and dome lights. I plugged the orange wire into the top left row circuit on the fuse box. The ribbon wires from green box marked "AC"remains plugged into the instrument panel just to the side of the speedometer cable. I see a recommendation to plug the actual green box into the speed sensor. I need to find the speed sensor, but first need to know what it looks like? Still no running and dash lights, the light switch is new, not sure what else could be the problem. As suggested by several of you, the grey and tan wires were speaker wires, so they are not an issue.

The big remaining problem is the 5 AMP fuse/circuit the powers the dash and running lights. If anyone has any ideas on steps to take for trouble shooting this circuit it would be much appreciated. Thanks again.

The ribbon cable on the green book leads up to the optical speed sensor inside the speedo head. There is a wheel with slots cut into it, the optical speed sensor counts how many times it “sees” the windows in a certain amount of time. It then uses that to calculate speed.

The 3 wire connector with yellow, pink and black plug into the other end of the A/C Delco green box.

 

[mgoldbach]

Okay, I replaced the 5 AMP fuse with a new one and checked the fuse box contacts (for the 5 AMP fuse) and they are both tight. Still no power at the orange wire connection at the light switch, thus no running lights. I started to check the orange wires from the light switch and I need to disassemble more of the dash to proceed. Please bear with me, I really appreciate your help with this. Thanks again.

 

[mgoldbach]

Matt69olds, Unless the connection part of the Green "AC" box is missing, right now it is not possible to connect the yellow, pink and black plug into the green box. Please see the enclosed photo. Thanks for your suggestion.

 

[mgoldbach]

Matt69olds My apologies, I physically tried to connect the yellow, pink and black plug into the Green AC box and it worked. Just from examining the plug I thought this will not work....little did I know. So with this plugged in, what does this do? Thanks again, you have been very helpful!

 

[Jgonick]

Okay, I replaced the 5 AMP fuse with a new one and checked the fuse box contacts (for the 5 AMP fuse) and they are both tight. Still no power at the orange wire connection at the light switch, thus no running lights. I started to check the orange wires from the light switch and I need to disassemble more of the dash to proceed. Please bear with me, I really appreciate your help with this. Thanks again.

Wrong fuse- you need to check the 20 AMP fuse for TL/CTSY
see attchment

 

[Matt69olds]

Matt69olds My apologies, I physically tried to connect the yellow, pink and black plug into the Green AC box and it worked. Just from examining the plug I thought this will not work....little did I know. So with this plugged in, what does this do? Thanks again, you have been very helpful!

It’s been a while since I put cruise on my truck. Let’s see how good my memory is!!

The connector with the pink, black and yellow wires are part of the cruise control harness. It uses the signal from the vss to command the servo for throttle position.

Somewhere in that cruise harness will be a plug for the cruise lever, another for the brake switch (there will be 2 brake switches, one for the brake lights, and another for the cruise and torque converter clutch) and a vacuum hose. The vaccum hose connects to a vacuum switch on the brake pedal. If the switch should electrically fail to turn off the cruise, the vacuum switch will dump the vacuum to the cruise servo and release the throttle. The last connector on the cruise harness is a brown wire that plugs into the fuse box.