Help Me See The Light ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

srprize · 09-23-2004, 02:22 AM

I stiil can't figure out how to hook up the back-up lights on my 70

1/2 ton stepside. On the side plate of my three speed manual where the 1st & Reverse shift fork comes out, there is what looks like a switch. It has a ball bearing at the end that rides against the shift fork shaft. the shaft has an offset cut into it that applies pressure to the ball bearing when in reverse.
the other end of the switch has a single electrical lead that attaches to it. But I dont' know how to hook it up.

HELP!

68C15 · 09-23-2004, 02:54 AM

I dont have my wiring diagram at home but I believe there should be a dark green wire that gets gounded when switch is activated. if I am wrong I hope someone tells me.
wait a minute, shouldnt there be 2 terminals on that switch? one from fuse box & the other goes to the lights?

Longhorn Man · 09-23-2004, 03:54 AM

While I have not worked on the manual shift trucks, and I too do not have my schematics here...
I think there is supposed to be two terminals. Very little on these trucks are switched through the ground side of the circuit, almost everything is on the power side. The lamps are grounded in the housing, and there are no relays anywhere in the lighting system, which is what it would take to have a ground turn on the power.
I'll bet a punch in the gut that you need a new switch. Then all it is is a matter of locating the two light green wires and plugging them in.

Longhorn Man · 09-23-2004, 04:15 AM

Hmmm, something odd here, and it may well be wrong, but in the latest LMC catalog, (page 154) they show the 3 spped manual as having the switch on the column like an automatic.
Is there a chance that your tranny is not original?
Now the punch in the gut bet is off the table. I proved myself wrong, so i'll punch myself.

Now, look under your dash at the bottom of the column, and see if there is a switch there with green wires plugged into it.

09-23-2004, 02:22 AM	#1
srprize Registered User Join Date: Sep 2004 Posts: 5	Help Me See The Light ? I stiil can't figure out how to hook up the back-up lights on my 70 1/2 ton stepside. On the side plate of my three speed manual where the 1st & Reverse shift fork comes out, there is what looks like a switch. It has a ball bearing at the end that rides against the shift fork shaft. the shaft has an offset cut into it that applies pressure to the ball bearing when in reverse. the other end of the switch has a single electrical lead that attaches to it. But I dont' know how to hook it up. HELP!

09-23-2004, 02:54 AM	#2
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	I dont have my wiring diagram at home but I believe there should be a dark green wire that gets gounded when switch is activated. if I am wrong I hope someone tells me. wait a minute, shouldnt there be 2 terminals on that switch? one from fuse box & the other goes to the lights? __________________ Man rule #77...if you own a 67 stepside with a caddy 472 you will never be in danger of loosing you man card

09-23-2004, 03:54 AM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	While I have not worked on the manual shift trucks, and I too do not have my schematics here... I think there is supposed to be two terminals. Very little on these trucks are switched through the ground side of the circuit, almost everything is on the power side. The lamps are grounded in the housing, and there are no relays anywhere in the lighting system, which is what it would take to have a ground turn on the power. I'll bet a punch in the gut that you need a new switch. Then all it is is a matter of locating the two light green wires and plugging them in.

09-23-2004, 04:15 AM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Hmmm, something odd here, and it may well be wrong, but in the latest LMC catalog, (page 154) they show the 3 spped manual as having the switch on the column like an automatic. Is there a chance that your tranny is not original? Now the punch in the gut bet is off the table. I proved myself wrong, so i'll punch myself. Now, look under your dash at the bottom of the column, and see if there is a switch there with green wires plugged into it.



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