[badmystur]

i recently bought a 74 gmc pickup my problem is when i pull out the headlight switch to the first click( for just marker lights on ) they do not come on, or do the tailights , but when its pulled all the way out the headlights /tail lights do come on,im looking for a very clear wiring diagram to try to figure this out, it apparently has a new headlight switch already any ideas would be much appreciated,,,,,,,,,,

[Chris Kemp]

I think you have a bad switch. This is how I would check the switch. To do this I would unplug the connector from the switch. I would use a test light to find the wire(s) that are hot. I would then make up a jumper from the hot supply moving it around touching it to all other wires testing to see if the lights light up like they are supposed to. If they do then you have a bad switch.

[richard stewart 3rd]

Hi,
The links will take you to a 72 gmc wiring diagram, hope it helps.
Good luck,
Rich
http://www.flickr.com/photos/boundst...10207/sizes/l/

http://www.flickr.com/photos/boundst...11656/sizes/l/

[crownver]

This is a 73-76 diagram from Chiltons

[crownver]

Try again. Forgotten how to do attachments. If it doesn't work this time I'm going to bed.

[crownver]

OK, this is definitely that last try

[joe_padavano]

The wires to the park and tail lights are the same, only the contacts in the switch are different. This pretty much narrows the problem down to the switch.

[Bryan59EC]

Switch x 2

[badmystur]

hey brian , and everyone else, much appreciated im going to try a new switch and see what happens,,,,,,,,,,thanks again guys,,,,,,,,,,