O.T. GMC dash lights

[Robert Zack]

Have another odd one for y'all. I've been on 3 GM forums & talked to 2 dealers, & 2 independent mechanics. I have a 2011 GMC Sierra 1500 ext. cab 4x4 truck. The main dash lights quick working at NIGHT! the gauge lights work but speedo & tach lights do not light up at night. during the day they work. there's a small smoke colored bulbous dome on the dash near the windscreen that I'm assuming is a light sensor of some kind. since the malfunction is at night I tried shing a bright light on that when it's dark. I carry a small flashlight to check my speed now & again while driving in the dark. Anyone come across this issue?? Fuses were all checked.

 

[ohiowa]

long shot. Faulty grounds can cause strange things to occur. Say those lights have a weak ground, but enough to light. if that ground is shared with other lights that come on at night they could cause the ground to fully open and then nothing works. Check that tail lights and others that are supposed to be on at night are working. Where that ground might be is anyone's guess.

 

[Robert Zack]

worth checking. my left rear light was acting like a bad flasher or i needed a heavy duty flasher like in the old days when you'd hooked a trailer. flashing was rapid fire. i looked everywhere for the flasher. turns out that function is computer driven & the flasher clicking comes from the driver's door speaker. i looked at a 79 ford with power steering & air and the bullet proof inline 300 6 cylinder. on the fence over parts worries & finding a mechanic as i'm too old to be climbing around & under trucks anymore. i recently read thar a classic car dealer closed due to a lack of people knowing how to work on a carb. these new vehicles have no soul.

 

[Eman85]

Is there a dimming function switch? When you turn the lights on the dimming function will control the dash lights, if it's turned down you won't have a lit up dash at night.

 

[Jim L WA]

worth checking. my left rear light was acting like a bad flasher or i needed a heavy duty flasher like in the old days when you'd hooked a trailer. flashing was rapid fire. i looked everywhere for the flasher. turns out that function is computer driven & the flasher clicking comes from the driver's door speaker. i looked at a 79 ford with power steering & air and the bullet proof inline 300 6 cylinder. on the fence over parts worries & finding a mechanic as i'm too old to be climbing around & under trucks anymore. i recently read thar a classic car dealer closed due to a lack of people knowing how to work on a carb. these new vehicles have no soul.

I think ohiowa is right about a bad ground. I know what you mean by being too old to be contorting yourself to get under a dash panel. As for the fast left turn on the left rear, did you check the left front?
Another suggestion is to look for an independent auto electric shop near by.
I don't want to start a brand war, but in my opinion, if you switch to that Ford, you will be better off.
Good Luck

 

[Robert Zack]

i should mentioned that outcome. there is an open electrical junction box on a rear frame crossmember near the bumper. there is a short section of wire harness just for the left rear taillight. i removed it & cleaned the contacts & coated the contacts with dialectic grease. that cured it for a few days. tried it again, no luck. i then replaced that section of harness & that fixed it. the dealer wanted 97.00 for a 16" harness. bought the same OEM harness online for 23.00 shipped. in the 70s a 4 cylinder head gasket set from a volvo dealer was near 100.00. local European auto parts store wanted 38.00. j.c. whitney catalogue sold it for 12.00. all 3 were the exact same parts with the same packaging marked made in Denmark. it pays to shop around.
i'm trying to reach a deal on the ford. it's not a brand thing it's an age thing. no computers. when you open the hood you can actually see the engine. i know how to work on it. what i cannot physically i can guide my grandson through it.

 

[Fixingfarmer]

Hmm I’ve had this same problem on the 05 Silverado intermittently. I know for sure it has had a left rear taillight harness in the last couple years (long story but had led lights that needed wires switched around. Went back to the original and decided just to replace that chunk instead of rewiring again.) strange that this would even be connected in my case I tried a sensor up in the dash and have just lived with it since. If you thump the dash it comes back I was going to try dimmer switch next. Seems like pressure around that area helps.

If the wife is riding I thump it and tell Mickey to quit it and get off the wires

it’s getting to the point I’m going to have to take another crack at it