Author Topic: lights not working in the instrument cluster, the interior and parking  (Read 220 times)

Offline plbwizard

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ok guys i have a grimlin in my truck and i can't find it. i will do my best to explain all i have checked so we don't have to go back over any of it but i may skip somethings by accident. my truck is a '85 gmc sierra classic 4x4 with the 305. the truck was bought new by my uncle and my dad bought it off of him in '89. my dad past away in '96 so the truck just kinda set at my moms house being used as a trash truck and a loner to my brothers every so often. i have repaired the things on the truck over the years as they would break or just go bad but all in all the trucks in about 75% condition. i finally found mom a smaller truck thats more reliable and easier for her to get in and out of so she just gave me my dads truck and i couldn't be happy. i brought the truck home about two months ago and wanted to get started on just getting road ready so i could just do some back road riding. i started by replacing all the belts, filters, and oil. once i got that i wanted to move to the lighting so i went to the interior lights. the dome light was working fine and so were the dash lights but there was one on the passenger side under the dash that was not working so i replaced the bulb but it still didn't come on so i thought thats odd but it hasn't worked in years and i thought i would look at it later. well then my attention moved to the cluster lights, they were very dim so i thought i would remove the cluster , something i've done before, and check the bulbs. now this is where it starts down hill. before i get the cluster out i notice the dome light has quit working so i wiggle the bulb, that has worked for me in the past, but not this time. well then i noticed the cluster lights has quit working as well not all of them only the ones controlled by the light switch, the brake indicator light and high beam indicator light are working fine. well i checked the fuse and had nothing so i pulled the fuse and it was good so i checked the hot side of the fuse(5amp inst) and had nothing there. i checked both sides of each fuse and found that along with the 5amp inst fuse nothing above that fuse had hot . its like one section of the fuse block is dead. i then went deep into it. i have checked the fuseable links coming from the stater, i checked the hot wires leading to the fuse block at the farewall, i replaced the light switch. i am getting and relacing the dimmer switch as soon as it arives because the old one would not dim. i have checked and cleaned the grounds on the drivers side ground bar. i do have headlights but no running lights, interior lights or dash light. i can jump a hot to the wire that goes to the running light and they work so does the dash lights but they will not work by the switch. i have looked for broken wires, i have took the fuse block apart and cleaned and checked it, i have traced wires from the switch that goes down to the back of the fuse block( the green wire) which goes to the part of the fuse block that does't have a hot. the green wire seems to be the how the 5amp inst fuse gets its hot along with everything above it but the green wire isn't hot. can someone please point me in the right direction on what to do next. i have looked at schematics till i'm brain numb. this lighting problem has stopped everything , i can't go any futher till i get this fixed. i have never let something stump me but this is dang close. thanks for any help
I am a professional tinkerer, please try this at home

Offline bd

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Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline plbwizard

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #2 on: September 13, 2019, 06:26:57 PM »
thanks Bd for the help. i am the first person to tell friends of mine, when they ask about trailer lights, " it's a ground issue " and just about 9 out of 10 times it is a ground issue. i have a question, do you think that when i put the new belts on i could have disrupted a ground somewhere ? i have checked/cleaned the one at the drivers side ground block and also the one at the passenger side farewall. i also checked the one coming from the battery ( the smaller black wire) to thr core support, it was just hanging but i fixed it when i saw it while i was putting the new belts on.
I am a professional tinkerer, please try this at home

Offline plbwizard

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #3 on: September 13, 2019, 06:34:37 PM »
im going to go now and follow the diagnosing steps you posted for me. again thanks a million and i will keep you up to date with how it goes.
I am a professional tinkerer, please try this at home

Offline bd

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #4 on: September 13, 2019, 08:11:22 PM »
Initially, I suspect there exist a series of oxidized or otherwise poor connections scattered about the wiring.  When you inherit such a nebulous project it is always best to begin by inventorying and physically verifying ALL of the ground connections back to the battery source, since ALL electric appliances rely on the ground path to function correctly.  If ground is not perfect, then all voltage measurements become suspect and power distribution randomizes helter-skelter.  Quick verification of cabin ground is to connect a voltmeter directly between the actual battery negative post and the ground bus bar under the dash to measure any accumulated voltage drop across the ground path while the interior and dash lights are switched on.  If the voltmeter deviates from zero, there exists excessive resistance in the ground path.  Once cabin ground is verified as 100% intact, you can then reliably follow up with voltage drop tests between the ground bus bar and the various appliances. 

When checking fusible links, give them a firm tug to see whether they stretch or separate and inspect the wire insulation and terminal ends for evidence of discoloration and heat stress. 

Carefully inspect battery cable connections for oxidation and tightness at both ends of each cable.  Make sure the battery-to-engine ground cable connection is clean, tight and appropriately attached to the alternator bracket or directly to the engine block.  Avoid ground cable connections to intake manifold mounting bolts, exhaust manifold bolts, and/or valve cover bolts.

Do I think you introduced a ground problem when you installed belts?  Unlikely, unless critical brackets were left loose. 
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline plbwizard

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #5 on: September 13, 2019, 10:13:23 PM »
success
I am a professional tinkerer, please try this at home

Offline plbwizard

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #6 on: September 13, 2019, 10:44:18 PM »
First let me say many thanks to everyone that takes their time to answer questions from guys like me , you don't really know what it means to us fellow weekend warriors. but most of all thank you bd for all you do in taking your time with this site , you are less than a God but more than human  :). i went over the links you sent me and read every word, eat dinner , then went to hunt down that grimlin armed with new knowledge . i had already went and checked all the grounds, cleaned and tightened , so i was confident that they were good. so i went back to the switch and done what the link said and thats when i found no + positive on the orange wires. i tracked the orange wires to the fuse panel, which i had to seperate by removing the two 5/16 th screws. when i put the test light on the orange wires in the back of the fuse panel i had nothing but i had already did a test on the fuses and they were working fine so i went to pull the fuse to inspect it and then it happened, the dash lights came on. i removed the fuse and just like you sad db, it had oxidized. both of the fuses were oxidized to the point to where they tested good but wasn't letting the + positive go to the orange wires . i can't beleive it was something so simple. if you could see my truck right now you would bust a gut laughing, over a oxided fuse, lmao. i couldn't have fixed this problem without you links and advice. the link you posted for me that showed what each wire went to at the light switch is what i had been looking for. i was thinking that the red wire was a constant hot to the switch and all the other wires wire only hot with the switch on, but i was wrong. the orange wire was supposed to feed the switch as well. once i knew that then i went from there and had it fixed in 10 minutes. again thank you so much. i will post a few pics of my truck and will update the pics as i do things to it.
« Last Edit: September 13, 2019, 10:47:56 PM by plbwizard »
I am a professional tinkerer, please try this at home

Offline bd

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #7 on: September 14, 2019, 12:25:45 AM »
Persistence pays.  Congrats!  And, thanks for the kind words. 
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 75gmck25

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #8 on: September 15, 2019, 07:10:35 AM »
One additional suggestion - there is a spray product called DeOxIt that I plan to try on some of the oxidized contacts and switches on my truck (bed light switch, headlight rheostat, etc.).  I'm not how effective it will be for the truck switches, but it worked well on the switch for an old radio I rebuilt.

Bruce

Offline JohnnyPopper

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #9 on: September 15, 2019, 08:40:38 PM »
BD is the man as usual!

Bruce, DeOxit is a wonderful product, I use it to service consumer electronics and can say with certainty that any vehicle with BUSS fuses would benefit from spraying and spinning the fuse in it's holder. If you can't make it spin, pry it out and clean it.


Offline bd

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #10 on: September 16, 2019, 11:46:58 AM »
Forever alert to effective products, which of the DeoxIT product line do (have) you use(d) - in 5% or 100% concentration - liquid, aerosol or wipes?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline JohnnyPopper

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #11 on: September 16, 2019, 03:23:27 PM »
I use two aerosol products, can only recall one is red and the other green. One works well with plastic, the other not so much...

I know this is a REALLY specific response... I have them at another location, will get the more technical info later today.

Offline bd

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #12 on: September 16, 2019, 04:37:07 PM »
Based on Caig Laboratories' website, red is the general-purpose juice, green is for carbon resistance potentiometers and faders, gold is for precious metal contacts.  It seems the 5% mix is most commonly marketed on Amazon, etc.  Which is easier on plastics?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline JohnnyPopper

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Re: lights not working in the instrument cluster, the interior and parking
« Reply #13 on: September 16, 2019, 04:52:29 PM »
Without looking at my two cans, I would say green as the equivalent of potentiometers and faders are what we clean on older analog components encased in plastic.

Did not know they make a 'gold', my supplier obviously doesn't carry it.