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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: bowdown916 on February 24, 2012, 07:36:01 pm

Title: Cab. Lighting info.
Post by: bowdown916 on February 24, 2012, 07:36:01 pm
Sup guys.was wondering if there suppost to be a fuse just for the inside cab under dash light and dome light?

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Title: Re: Cab. Lighting info.
Post by: zieg85 on February 24, 2012, 08:14:35 pm
The under dash light is independent to my inside dome light on my 85 C20 but both goes on when I open the door.  I have blown my horn fuse before and the dome light quit working but under the dash still worked.  If I tried to use the horn with the fuse blown the relay would flutter and so would the light.  Weird and I don't know if something is wired wrong or something my uncle cobbled up.
Title: Re: Cab. Lighting info.
Post by: 1979C20 on February 24, 2012, 10:39:30 pm
The "HORN/DM" fuse is for the horn and the over head dome light, and the "TL/CTSY" fuse is for your tail lights and the under dash Courtesy light.
Title: Re: Cab. Lighting info.
Post by: bowdown916 on February 27, 2012, 06:39:05 pm
ill check into that, the dome light,its orange wire n white right, orange its power and connecteds to the fuse box?
Title: Re: Cab. Lighting info.
Post by: 1979C20 on February 28, 2012, 12:09:40 am
Correct. The orange wire connects to the fuse box and goes to the positive on the light. The white wire comes from the dimmer switch, and both of the door pins and send a ground signal to the light.
Title: Re: Cab. Lighting info.
Post by: bowdown916 on February 28, 2012, 12:16:22 am
Umm.ok then the problem its im not getting power where the orange wire connects to the box, i checked those 6 free open spaces n none had power.
Title: Re: Cab. Lighting info.
Post by: 1979C20 on February 28, 2012, 01:24:25 am
Check the "ACC" fuse. Its for the accessory outputs on the fuse box. It may be the problem.
Title: Re: Cab. Lighting info.
Post by: bowdown916 on February 28, 2012, 01:35:25 am
If the fuse its fine. Can i put like a jumper wire from other 12v space to feed the orange wire?
Title: Re: Cab. Lighting info.
Post by: bake74 on February 28, 2012, 06:29:12 am
If the fuse its fine. Can i put like a jumper wire from other 12v space to feed the orange wire?

     I know electrical can be a P.I.T.A. sometimes, but electrical is the one place you do not want to make short cuts.  Patience and knowledge is key when working with electrical, do all you can to research the problem and if need be ask for help to figure it out.
     In the short time jumping it could work, but if you jump it from the wrong circuit and say you put an extra load on that circuit, now you will have a problem with another circuit and still not have fixed the original problem.
     See where this is leading to ?
Title: Re: Cab. Lighting info.
Post by: bowdown916 on February 28, 2012, 10:16:40 am
Yea,  i might be making another problem in the future.. but that top left side of the box where those 6 free spaces are,  they suppost to have power right?
Title: Re: Cab. Lighting info.
Post by: aaronwilliams on February 29, 2012, 10:08:32 am
The wiring diagrams in the technical pages on this site are fantastic. Thank you Capt

Complete 73-87 Wiring Diagrams
http://forum.73-87chevytrucks.com/smforum/index.php/topic,11766.msg87585.html#msg87585

Im not sure about the older trucks but for 81-87;
if you look at the 'instrument panel page 2' it shows the fuse panel. the top left fuse powers the next circuit up from it, which in my late 80s trucks says 'shunt'. The shunt is just a jumper(buss) which powers up the two columns its attached to. so replacing the fuse should power up the terminals above it on that side. you can verify by checking continuity from the left fuse terminal to the upper terminals.

also note these lights are normally hot and have a switched grounds. You are checking this with the door open so your door jam switch is grounding/completing the circuits your working on.
Title: Re: Cab. Lighting info.
Post by: bowdown916 on February 29, 2012, 01:17:07 pm
if i dont find the same door switches locally then ill order some from  , i got a feeling they might be bad,but well see.. all the wiring from right door switch to left looks fine.. but also gotta check that fuse, if you see on the pic where the white/orange wire connects to the top left. those 6 open spaces dont have power,so gotta check that too..