No signal says no signal when plugged in

New set will have a plug on it so don't be concerned about just cutting the plug off to get the old harness out. You have to remove the steering wheel and anything above the turn signal switch to give access to the little pivot bolt the switch is mounted by. Remove this pivot screw/bolt and pull the unit out. After the plug has been cut off the end of the signal harness, the wires will come out easily. Put all that aside, grab your new turn signal unit, Turn the plug on it's side, flat on the wires, and feed it down thru the column housing until the new switch is in position to bolt back on. Now put it back together in reverse of removal.

if you have a right signal on the truck and no signal on the trailer then you need to check the wire were it comes from the truck wire harness to the trailer plug. possibly a bad trailer plug also

get the standard wiring design
http://www.narva.com.au/products/browse/wiring-diagrams
Yellow is the left turn signal on pin 2
Check trailer plug and see if correct colors used on trailer plug
Would suggest getting a 12volt probe so you can test the car socket when left indicator is going on - flashing
To check that the correct pin has 12volts flashing left on it.

whichi fuse? only when right turn signal. not left. ?

Fixya

Check the plug at your gmc outlet, your right signal wire has been damaged before the plug somewhere. If you have a test light switch your right signal on and make sure it is working at the plug on your gmc, you will find it is not working, than trace the wire back from the plug till you find where it has been damaged or you can run a wire straight from plug to your right signal.

Remove or disconnect the following:

• Connector
• Screw
• Claw fitting
• Front turn signal lamp assembly
• Front turn signal lamp plug assembly
• Front turn signal lamp bulb as shown

To Install:

1. Install or connect the following:
   • Front turn signal lamp bulb
   • Front turn signal lamp plug assembly
   • Front turn signal lamp assembly with screw
   • Connector

Could be a problem in the flasher unit. Or could be a problem with the turn signal switch. Cheapest would be to replace the turn signal unit or relay.

If you have an aftermarket trailer plug on your truck, you are going to want to inspect the wiring to the plug, and the connections in the plug. I think it's shorting out.

ok tdknutson, I'm not clear on this, does the truck left turn signal stop working when u plug the trailer in, or is it the trailer left turn signal that's not working, or both? When u plugged in the test light did it show u had power to that plug in? Let me know the answer to the above, and in the meantime, check the ground on the turn signal at the trailer. Make sure it's not loose, and tightly connected to the frame (or wire). Also, what type plug in do u have? 4, 6, 7 wire?

Connector Part Information
• 7223-9730-30 • 10-Way F (GY) Pin
Wire Color
Circuit No.
Function
1
BN
1271
Reference Low Signal
2
WH/BK
1164
5-Volt Reference Signal
3
L-BU
1162
Throttle Pedal Position Signal
4
--
--
Not Used
5
BU
1161
Throttle Pedal Position Signal
6
TN
1274
5-Volt Reference Signal
7
PU
1272
Reference Low Signal
8-10
--
--
Not Used


Hope that helps, Good Luck