Parasitic Draw Testing
Auto Electrical Repair — Cheyenne, WY
If your battery dies overnight or the truck won't start after sitting a few days — and the battery and alternator both test good — something on the vehicle is staying awake and drinking current when it should be asleep. That's a parasitic draw, and common culprits include modules that never power down, glovebox and hatch lights, aftermarket accessories, and trailer wiring gone wrong.
Finding one is pure method: measure the draw, then isolate it circuit by circuit through the fuse boxes until the offending circuit — and then the offending component — is identified. It's exactly the kind of patient electrical work TDC is set up to do, and it beats buying batteries over and over.
What's Included
- Overnight and multi-day battery drain diagnosis
- Draw measured and isolated circuit by circuit
- Aftermarket accessory and trailer wiring faults found
- Module sleep-state problems identified
- Stops the battery-of-the-month habit
Electrical Diagnosis, Step by Step
- Define the symptom
When it happens, what changes it, what else acts up at the same time — electrical faults leave patterns.
- Test the circuit
Voltage, ground and load testing at the component and along the circuit narrows the fault to a segment.
- Find the actual fault
Broken wires, corroded connectors, failed components — confirmed by measurement before repair.
- Repair and verify
Proper wiring repairs (soldered and sealed, not twisted and taped) and the fix verified under real conditions.
Related Electrical Services
Frequently Asked Questions
How much does parasitic draw testing cost at TDC Automotive?
Labor is billed hourly at $125/hr for gas vehicles and $135/hr for diesel, and you'll get findings and an estimate before repair work begins. Call (307) 996-0980 with your year, make and model and Trevor can give you a realistic idea of what's involved.
Do I need an appointment for parasitic draw testing?
Call ahead at (307) 996-0980 — as an owner-operated shop, TDC schedules work so your vehicle gets Trevor's full attention rather than sitting in a lot for a week.
Where is the shop, and what area do you serve?
The shop is at 8407 Aztec Drive in Cheyenne, Wyoming, and serves all of southeast Wyoming plus the Nebraska panhandle and Northern Colorado — customers regularly drive in from Laramie, Wheatland, Torrington, Pine Bluffs, Wellington, Fort Collins and Greeley.