bright lights?

[Buckman]

guys I have a 71 gmc swb, when you but on the bright lights are all 4 lights on? It seams to me that only the two outside lights go bright to dim. The 2 outside lights do look different from the 2 inside lights. Did someone wire these up wrong?

[Stocker]

They are working as designed. The outer lamps are dual filament high/low, and the inner ones are high only (single filament).

[Buckman]

Stocker you are saying that when the lights are on high then all 4 lights should be on.

[GMC AMI]

High beam would be all 4 lights.

[Longhorn Man]

Is there a chance that your GMC is a chevy wearing a GMC nose?

[Stocker]

Buckman, High beam = all 4 lamps on.

Low beam = only the 2 outer lamps are on.

The way I understand your post, this is the way yours are working.... right?

[Buckman]

My inside lights do not work at all

The outside lights change from High beam to Low beam

[stueber68]

Stocker is right. The inside set of light on these trucks are the high beam. They have a two plug terminal on them. The outside lights are the low beam and they have three terminals. Now if you find that all of the connections are right on the back of the bulbs you need to check to see if the grounds for the lights at the core support are good and also at the dimmer switch on the floor. If all of these are good you may have a bad dimmer switch. Keep us posted on your progress.

[Longhorn Man]

no, his dimmer switch is workin fine...the outers are both high and low.... since they are switching, then the switch is doing it's job.
Not likely to be a ground isse either...could be, but not likely.
Check the connections, see if you are getting power to them, if so, then you need lights (after looking at the grounds too) If not, then back track untill you find the break in the wire.