Headlight wiring, no running lights

[Heavymetalmechanic]

First off, awesome group of people on here! I have been hunting for posts relating to my problem but have not had any luck yet, just gave me a great reason to join.

1994 2Dr 4x4 Yukon, 5.7L, 5 speed manual

My center low beams are always on with no switches selected, my lower and outer amber marking lights only come on when I select both dash light switches (top switch does not turn on anything). I can not turn on the outer upper headlights, or get power to them. All dash switches test ok. Column high beam toggle switch push rod is stuck. (tomorrows starting point). To make maters worse the wiring colors for the drivers side high beam lamp do not match my Chiltons diagram. (shows as black, light green and tan, plug only has light green and dark blue with white line). I am the newest owner, last guys did some really half-baked jobs of wiring in stereos, subs/amps and trailer harness, I just spent 4 hours removing disconnected aftermarket wiring to try and clean up the engine bay harness. I have at least 4 hours of work unwrapping electrical tape connections at the fuse and junction block before I can start tracing and testing under the dash.

Have any of you had similar issues?

What are some good resources for wiring diagrams?

It is my understanding that the 1994 1500 series Yukons were unique in a lot of ways (heavy duty cooling package etc.) so I am curious to see if this is a stand alone problem or common to other years and models. This truck is my first foray into customizing a 4x4 and I am working with a very limited budget (scrapyard parts only, other then gaskets and seals.). It is also currently (unfortunately) my daily driver which limits how far I can rip it apart for learning perposes. I have a full tool kit (lic. HD Mech) and access to specialty tools at work so I'm in good shape for everything except the priceless off roading experience.

I am looking forward to bouncing ideas off all of you, thanks for taking the time to chew through this long post.

 

[99Yuk]

Welcome to the place, pull up a chair and hang around a bit!
Good to see another CDN here.

Yup, this place is chock full of good ideas and good people.
Cool that you made up a sig with your trucks details on it. Makes it easier to help.

I think tomorrow, you'll find the 'Column high beam toggle switch push rod' being stuck is the cause of your High beams not comming on.

Sounds like your on the right track for undoing the wiring that the PO did.

Some good sources for wiring diagrams are Mitchell on Demand or All-Data. Both are good. There are a few guys here who have subscriptions. Odds are that if you ask for a specific diagram, then they will post them up.

GL and feel free to ask questions.

 

[SunlitComet]

As you describe it all those point to a multiswitch unit in steering column that is in dire need of replacement. and maybe the headlight switch as well if the low brightness bulbs in lower half parking/turn signal assembly do not light up. with ignition on the low beams will always be on either as drl or headlights when head switch is all the way on. Start only with your multiswitch which will do turn signal, hazard, brake(sorta), turn controls as well as high low beam selection.

Also when parked ignition on depress your parking brake. If low beams go out and the indicator light on cluster disapears your DRL function is normal. Both should turn back on when you release the parking brake. If the low brightness parking lights still do not work do your headlight switch.

BTW you diagram refers to sealed one piece headlight beams.

You need to look at the one for quad lights.

It doesn't sound like those hack jobs are causing your problems so far.

Don't forget about fuses too.


And as 99Yuk said we do have diagrams. I have diagrams that should cover all years in this group.

BTW I would start looking for a second job now that you have found this place.

 

[Heavymetalmechanic]

Thanks guys, I will be visiting pick'n'pull tomorrow to grab that multi switch. I will update as I make progress.

 

[Heavymetalmechanic]

Turns out the problem is that the high/low beam selector rod has dropped out of the multiswitch, devil of a time trying to get that back in, no success yet.

 

[SunlitComet]

Know money is tight but you are probably better off replacing the whole thing as the assembly covers a lot of different functions.

 

[Heavymetalmechanic]

Ya, I'm leaning that way already. The lower column cover is broken and I want to replace that while I'm at it. On a different note, I got my aux battery wired in last night, now I just need to track down a winch, inverter and electric heater...