Diesels run two batteries. Both have to be right.
Battery, Starting & Charging
Most no-start calls are not the battery itself — they are a corroded terminal, a failing alternator, a bad ground or a parasitic draw quietly killing the charge overnight. We load test the whole system before selling you anything.
Diesel trucks with dual batteries need matched, healthy pairs. One weak battery drags the other down and cooks the alternator, so we test and replace them as a set when they need it.
What's included
Scope of work
- Battery load test and state-of-health report
- Dual-battery testing and matched replacement on diesels
- Alternator output and ripple testing
- Starter draw testing and replacement
- Parasitic draw diagnosis with fuse-box isolation
- Terminal, cable and ground repair
- Fusible link, relay and wiring harness repair
- Trailer plug and 7-pin wiring repair
Symptoms we fix
Sound familiar?
- Slow crank or clicking with no start
- Battery dead after sitting a day or two
- Dash lights dim or flicker at idle
- Battery or charging warning light on
- Corrosion built up on the terminals
- Accessories reset or behave erratically
How we work it
The four steps, every time
- 01
Test
Battery, starter draw, alternator output and voltage drop across cables and grounds.
- 02
Isolate
Parasitic draw is traced circuit by circuit until the culprit is found.
- 03
Repair
Correct group-size battery, proper cable ends and clean grounds — no bolt-on shortcuts.
- 04
Confirm
Re-test charging under load with accessories on before you leave.
Questions
Straight answers
Do I need both diesel batteries replaced?
If one is failing and they are the same age, yes. Mixing a new and a tired battery shortens the life of both.
My battery keeps dying overnight.
That is a parasitic draw. We measure it and trace the circuit rather than replacing batteries until one sticks.
Do you install trailer wiring?
Yes — 7-pin and 4-flat repair, brake controller wiring and lighting circuits.
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Get a straight answer on your truck.
Tell us what it's doing. We'll tell you what it takes — in writing, before any work starts.