GMC

GMC troubleshooting questions? Ask a mechanic for answers

Ask an Expert,
Get an Answer ASAP!

88 GMC 2500 -- Electrical issue with lights. Brake lights…

Customer Question
88 GMC 2500 -- Electrical...
88 GMC 2500 -- Electrical issue with lights. Brake lights won't come on, right rear blinker won't turn on. Need help figuring out where wiring issue is, so I can fix it.
Submitted: 4 months ago.Category: GMC
Show More
Show Less
Ask Your Own GMC Question
Answered in 21 minutes by:
1/24/2018
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago
roybelding
roybelding, Master Tech/Trainer
Category: GMC
Satisfied Customers: 7,596
Experience: 35 years of retail operations on all vehicles
Verified

hello, my name is ***** ***** I will be glad to assist you. please allow me a couple of minutes to gather some basic info.

Roy

Ask Your Own GMC Question
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

the power needs to be verified at the brake light switch. if it is good test the output of the switch when you depress the brakes. if that is good, it goes to the turn signal switch and then out to the brake lights and turn signals.

diagram attached.

Roy

Ask Your Own GMC Question
Customer reply replied 4 months ago
Okay. I have battery voltage at brown wire going into brake switch with key on. There are two wires going into brake switch, brown and light green. How do I test the output?
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

press the brake pedal and test the light green wire

Ask Your Own GMC Question
Customer reply replied 4 months ago
Sorry, gray wire has power at all times.
Customer reply replied 4 months ago
Grey and green not brown and green. Sorry.
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

ok, you need power in and the other wire should have power when you push on the pedal.

is this a van or pick up???

Roy

Ask Your Own GMC Question
Customer reply replied 4 months ago
Pickup. I've taken the switch out, so it's hanging. If I understand it correctly normal function when the brake pedal is not the pressed the button on the switch is depressed. And when you press the brake pedal the button on the switch actually opens up. What is happening, is that when the brake pedal switch is depressed, meaning of the brake pedal is not depressed I believe, there is battery voltage out of the switch. That seems opposite to me to what it should be.
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

nope that is good. from there it goes to the turn signal switch.

the wire that has power with the button out needs to be checked at the turn signal switch connector for power.

if it has power then most likely you have a bad turn signal switch. if it does not have power then you a wiring issue between the brake light switch and the turn signal switch

Roy

Ask Your Own GMC Question
Customer reply replied 4 months ago
One symptom is that unless you pull the 15 amp STOP fuse, those lights stay on all the time, even with the key out of the truck.
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

you stated in your post the brake lights did not work????????

Ask Your Own GMC Question
Customer reply replied 4 months ago
Sorry, in the back there are six lights, three on each side. Reverse lights work sometimes... Have to fiddle with the shift lever to get them to work. The other two lights on each side are on all the time if the fuse is in, even with key out of truck. On the left side, one is really bright, and the other really dim. On the right side both really dim. Press the brakes, and nothing gets brighter. Shouldn't even be on without headlights on, but they are, and they don't light up brighter when brake pedal board pressed. Push hazard lights in, on the dash it glows green but nothing blinks. Turn them off and Turn the left turn signal to left blinker, and both sides (four bulbs) in the back blink like hazard lights, but hazards are off and it's only the back blinking.
Customer reply replied 4 months ago
just as I say that, I just turned the truck off, and now the tail lights are staying off without having to pull the fuse. Seems like it's different just about every time we start the truck or try to use it..
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

the first thing I would do is replace the stop light switch.

then go to the dim side and check the connector and the bulb. be sure the ground is clean and tight then re check

Roy

Ask Your Own GMC Question
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

Please take a moment and rate my service 3 stars or better. that is the only way the site will pay me for my efforts.

Roy

Ask Your Own GMC Question
Customer reply replied 4 months ago
the switch I was testing before? Replace it? (Brake pedal switch?)
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

correct that is the brake light switch

Ask Your Own GMC Question
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

any update

Ask Your Own GMC Question
GMC Mechanic: roybelding, Master Tech/Trainer replied 4 months ago

do you need any other help

Ask Your Own GMC Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a gmc mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask roybelding Your Own Question
roybelding
roybelding
roybelding, Master Tech/Trainer
Category: GMC
Satisfied Customers: 7,596
7,596 Satisfied Customers
Experience: 35 years of retail operations on all vehicles

roybelding is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

He answered my question promptly and gave me accurate, detailed information. If all of your experts are half as good, you have a great thing going here.

DianeDallas, TX

< Previous | Next >

Meet the Experts:

Gm Tech (Cam)

Gm Tech (Cam)

GMC Mechanic

1,795 satisfied customers

GM Grand Master Technician 2007. 14 year experience.

Gary

Gary

ASE Certified Technician

1,588 satisfied customers

GCM master tech over 25 years

Dave Nova

Dave Nova

GMC Technician

929 satisfied customers

ASE Master Certification. GM World Class Certification

Chris (aka-Moose)

Chris (aka-Moose)

GMC Technician

626 satisfied customers

16 years of experience

Ron Z.

Ron Z.

- GMC Tech -

279 satisfied customers

18+yrs experience. State Inspector & GMC Diagnostics/Repair

JFN1

JFN1

ASE Certified Technician

269 satisfied customers

GM Master Technician

George H.

George H.

ASE MasterTechnician

228 satisfied customers

15+ Years ASE Master Technician with Level 1 Certification

< Previous | Next >

Related GMC Questions
Service trailer brakes and abs light on, replaced trailer
Service trailer brakes and abs light on , replaced trailer brake mod under the bed of my 2007 gmc 2500 duramax . Still say service trailer brakes. Checked fuses they are good . Replaced both front hud… read more
Gm Tech (Cam)
Gm Tech (Cam)
GMC Mechanic
Vocational, Technical or Trade Scho
1,795 satisfied customers
Brake lights come on when parked killing the battery. I
Brake lights come on when parked killing the battery. I changed the switch above the brake pedal but it still is happening. You think it is the ignition switch? … read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
626 satisfied customers
My headlights won't go off. I have No idea how to check the
I have Tried turning the switch to off. There is also a button that controls the dome an fog lamps. I have Tried pushing it in and out. … read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
626 satisfied customers
09acadia brakelightandstabilirac. 09acadia brake and
09acadia brakelightandstabilirac JA: What is the model/year of your GMC? Customer: 09acadia brake and stabilitrack lighton // JA: Have you checked the brake fluid? How's the level and when was it last… read more
JOHN aka Eauto
JOHN aka Eauto
self employed
High School or GED
10,498 satisfied customers
Both low beam headlights not working; high beams fine,
Both low beam headlights not working; high beams fine, running lights fine … read more
Dan
Dan
Automotive Technician
Vocational, Technical or Trade Scho
158 satisfied customers
99 safari van, headlights won't turn off, fan motor runs
99 safari van, headlights won't turn off, fan motor runs continuously, right indicators stay on, not flashing. Ignition off, key out. … read more
Amedee
Amedee
Automotive Consultant
Vocational, Technical or Trade Scho
19,086 satisfied customers
No interior power, have power to fuse box and battery is
No interior power, have power to fuse box and battery is fully charged … read more
Chris (aka-Moose)
Chris (aka-Moose)
GMC Technician
Vocational, Technical or Trade School
626 satisfied customers
Headlights go on by their self any time day or nite. My
headlights go on by their self any time day or nite … read more
Gm Tech (Cam)
Gm Tech (Cam)
GMC Mechanic
Vocational, Technical or Trade Scho
1,795 satisfied customers
Headlights were working yesterday evening. We got in to
Headlights were working yesterday evening. We got in to leave this morning . . . No headlights. 2004 Yukon Denali We are wondering about a fuse but should we consider other possible issues? Thanks… read more
Amedee
Amedee
Automotive Consultant
Vocational, Technical or Trade Scho
19,086 satisfied customers
When headlight switch is on brings brake lights on solid and
when headlight switch is on brings brake lights on solid and blinkers will not work … read more
Mechanic01
Mechanic01
2,798 satisfied customers
To replace the low beam headlight bulb on the passenger
To replace the low beam headlight bulb on the passenger side, it would help to remove the air cleaner for my diesel GMC 2500 truck. It's an 09. How do you remove the filter assembly? I've got the cove… read more
Todd Audette
Todd Audette
Automotive Technician
Vocational, Technical or Trade School
362 satisfied customers
Low beam headlights wont work. Both lights arent working
both lights arent working checked fuses relay etc removed bulb it does not look blown … read more
Gm Tech (Cam)
Gm Tech (Cam)
GMC Mechanic
Vocational, Technical or Trade Scho
1,795 satisfied customers
Battery will not charge. new battery and new alternator. The
battery will not charge. new battery and new alternator … read more
Cesar Jimenez
Cesar Jimenez
Owner/CEO
Vocational, Technical or Trade School
171 satisfied customers
My e-brake light won't turn of and I believe the e-brake
My e-brake light won't turn of and I believe the e-brake won't release. The ABS light won't go off either. This just started yesterday.… read more
Todd Audette
Todd Audette
Automotive Technician
Vocational, Technical or Trade School
362 satisfied customers
New battery drains overnight. No but the battery is new. The
No but the battery is new. The same thing happened before the battery was replaced. … read more
Amedee
Amedee
Automotive Consultant
Vocational, Technical or Trade Scho
19,086 satisfied customers
I'm replacing the old headlights with led headlights. I was
Second opinion] I'm replacing the old headlights with led headlights. I was wondering what's the easiest way to change out the bulbs on a 2007 GMC Sierra 2500hd? … read more
Gary
Gary
ASE Certified Technician
Vocational, Technical or Trade Scho
1,588 satisfied customers
I'm replacing the old headlights with led headlights. I was
I'm replacing the old headlights with led headlights. I was wondering what's the easiest way to change out the bulbs on a 2007 GMC Sierra 2500hd? … read more
Peter Zavarelli
Peter Zavarelli
Automotive Diagnostic Specialist
General auto certifications
408 satisfied customers
With the engine running an turn the headlight switch on the
with the engine running an turn the headlight switch on the engine goes into reduced power mode. If you pull the dimmer the engine dies. … read more
roybelding
roybelding
Master Tech/Trainer
7,596 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x