How to Jump-Start a Diesel Truck

Do you prefer a diesel vs. a gasoline truck for your Cartersville or Rome area drives? A diesel GMC truck offers better towing power, pound-for-pound, versus a gasoline engine. However it may need some extra maintenance every once in a while. It’s not uncommon for diesel trucks to have more than one car battery. 

Every once in a while, your diesel truck battery might die because an electrical system ran for too long without the engine running, or perhaps the battery was near the end of its operational life. We’ll show you how to jump-start a diesel truck with two batteries with our guide from Welborn GMC Of Cartersville near Acworth. We hope it helps you have a better driving experience in Canton and beyond.

How to Jump-Start a Diesel Truck With Two Batteries: Supply List

The reason why your vehicle has more than one diesel truck battery is that it takes more cranking amps to start the engine. Luckily, you only have to connect one of those two batteries when learning how to jump-start a diesel truck with two batteries. 

See the supplies you need for this:

1. Robust jumper cables at least 10 feet long
2. A second vehicle with a working battery to supply power to the dead battery

The second battery can come from another vehicle with a working battery or a portable battery jumper for your truck that you can buy at automotive supply stores. 

Another option is to use a jump-start service, typically through a towing service or a service center that offers mobile services. If you can’t find a friend with a working vehicle, this service can come in handy!

How to Jump-Start a Diesel Truck With Two Batteries Properly

Now, we’ll go step by step on the proper way to jump-start a diesel truck. 

1. Have the two vehicles face each other with the batteries as close as possible. 
2. Turn off both vehicles and turn off all of the accessories in both vehicles to get the most out of the charge.
3. Set the parking brakes so that they don’t accidentally roll away. 
4. Raise the hood on both vehicles.
5. Locate the batteries. 
6. You only need to connect one of your two diesel truck batteries to make this work.
7. Find the positive and negative battery terminals. The positive terminal is typically red while the negative terminal is usually black.
8. Get out the jumper cables. 
9. Separate the red ends from the black ends on the jumper cables.
10. Make sure the ends of the jumper cables don’t touch each other. That could create a short circuit. 
11. Connect a red clamp to the positive post on the dead battery.
12. Clip the other red clamp to the positive terminal of the working battery with the charge.
13. Connect the black clamp to the negative post on the good battery. 
14. Connect the last black clamp to a grounded, unpainted metal surface on your car’s frame. Look for a metal bar or part that keeps a portion of the engine in place as the ideal piece of metal for this.
15. PRO TIP: It’s vitally important to connect the jumper cables in this order. Otherwise, your diesel truck won’t jump-start.
16. At this point, the electrical connections are made, so don’t touch the clamps or the terminals. You could cause a spark, or you could even drain the good battery and then the truck won’t jump-start due to low juice from the helper’s battery.
17. Start the engine of the vehicle with a good battery. 
18. Let the vehicle with a good battery run for a bit to strengthen the battery.
19. PRO TIP: Gradually press the accelerator of the vehicle with the good battery until the RPMs of the engine get to about 1,500. Idling is around 800 RPMs. The person in the good vehicle will notice a dip in the power when the vehicle with the dead battery tries to start the engine. If the vehicle with the good battery stalls, your truck won’t jump-start.
20. Try starting the engine on your diesel truck with two batteries.
21. PRO TIP: It may take some time for your diesel truck battery to recharge, so it may take a few minutes.
22. If the vehicle with the dead battery starts, allow it to keep running.
23. Carefully remove the jumper cables in the reverse order that they were placed while keeping both vehicles running.
24. Make sure the metal clamps don’t touch each other when you remove them!
25. Remove the black clamp from the unpainted metal surface first, then remove the other black clamp, then the red clamp on the good vehicle, then the red clamp on the vehicle that needed the jump-start.
26. Close the hood.

How to Charge a Diesel Truck With Two Batteries

Next, you’ll need to know how to charge a diesel truck with two batteries so you don’t run out of juice again. Your truck’s alternator can help with this.

1. Keep the engine running on the jump-started vehicle for at least 20 minutes. This will allow the alternator to recharge the battery for a time. It ensures you’ll have a fresher battery when you next turn off the engine. You can put your foot on the gas without driving anywhere or go for a short drive.
2. Drive home or to your next destination!
3. If you notice you need a jump-start again soon after, there might be another problem with your vehicle. Consider calling a jump-start car service or a tow truck to bring your vehicle to a service center after you see how to charge a diesel truck with two batteries.

How Long Do Diesel Truck Batteries Last?

Diesel truck batteries last around four years. However, that is an estimate. This number can depend on the climate, how much you drive, and the battery itself. Taking care of your truck and driving well can lengthen how long diesel truck batteries last, giving you a better driving experience.

Contact Welborn GMC Of Cartersville for Trusted Car Service

Does your vehicle need service for any reason? Contact us or call (770) 383-1679, and our team will take care of you. We’re happy to help in any way we can!