Click on image for the lowdown. 
====
| | |
12 members (jmoore, 3B, 55shaker, papas52, 2-Ton, Jay R, Joe H, GMCJammer51, Bucker, sron48, Shade Baby, Gray_Ghost),
120
guests, and
2
robots. | | Key: Admin,
Global Mod,
Mod | | | Forums66 Topics128,157 Posts1,056,894 Members48,458 | | Most Online14,466 Apr 26th, 2026 | | AD Chevy Trucks Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down with Ads! Again, thanks! | | | | Joined: Apr 2018 Posts: 80 Shop Shark | | Shop Shark Joined: Apr 2018 Posts: 80 | I have a question on my DC (ammeter gauge. It is a 12v system. I neglected to mark the wires after removing them from the back of the gauge. I know not very smart of me. Anyway I have 5 wires coming from the following areas - one from the alternator, one from the solenoid, one from the headlight switch, one from the ignition key, and one from the fuse box. My question is which wires go to the positive post on the back of the gauge, and which wires go on the positive side of the gauge. thanks for your help. Robert | | | | | Joined: Mar 2011 Posts: 1,146 Shop Shark | | Shop Shark Joined: Mar 2011 Posts: 1,146 | I think you mean positive post and negative post on the ammeter. This 1949 Truck Wiring schematic might help. The schematic is for the original 6 volt system, you said your truck has been converted to 12 volts. Do you have a 12 volt alternator or 12 volt generator ? Do you have a voltage regulator ? Do you have a foot starter or a solenoid starter ? The Ammeter's rear post, are determined by using the markings on the face of the gauge. The (D -) Discharge is your Ammeter's Negative post. The (C +) Charge is your Ammeter's Positive post. There is no battery negative voltage connect to the ammeter, only positive voltage. The ammeter shows if the battery is charging or discharging. Above 0 + Positive or below 0 - Negative. | | | | | Joined: Apr 2018 Posts: 80 Shop Shark | | Shop Shark Joined: Apr 2018 Posts: 80 | Yes it is converted to 12v by a previous owner. I have a 12v alternator. I do not have a voltage regulator. I have a push button starter. I do have a solenoid. | | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | It doesn't matter on the ammeter, if it indicates backwards(+ when headlights on), just switch the wires.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires. '47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle. '54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed. '55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
| | | | | Joined: Apr 2018 Posts: 80 Shop Shark | | Shop Shark Joined: Apr 2018 Posts: 80 | Ed. So the wires from the alternator, the solonoid and the ignition all attach to the C + chrge, and the wire from the headlight and fusebox go to the D- charge? | | | | | Joined: Apr 2018 Posts: 80 Shop Shark | | Shop Shark Joined: Apr 2018 Posts: 80 | Thanks but I'm still not clear where to connect the wires. Read above I have 5 wires to connect to the gauge. What wires connect to what side of the gauge +, -. | | | | | Joined: Mar 2011 Posts: 1,146 Shop Shark | | Shop Shark Joined: Mar 2011 Posts: 1,146 | Not knowing exactly what have and how the 12 volt conversion has been wired. It would be better to let someone with a lot of experience in 12 volt conversions to advise you on how to proceed. It is hard to advise someone on how to wire their truck unless you are there in person. These guys would know where those wires go, at least they would ask the right questions. Here is a link to YNZ Yesterdays Parts they build wiring harness. The thing is, there are different types of alternators and each are wired differently. | | | | | Joined: Apr 2018 Posts: 80 Shop Shark | | Shop Shark Joined: Apr 2018 Posts: 80 | Its a singe wire Alternator. Getting back to the Ammeter. As I understand it the charging side + is connected to the battery (10 gauge red wire), and the other items namely the headlight switch, the Alternator, and ignition key are connected to the D - side.. | | |
| |