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A wiring harness is the bundle of wires and connectors that carries power and signals between the battery, the computers and every light, sensor and motor. Route 66 Auto Repair in Upland repairs harnesses that were chewed by rodents, cooked near an exhaust manifold or corroded at a connector. Our ASE-certified technicians test each affected circuit, show you the damage in photos, and put the repair plan on a written estimate before a single wire is cut.
What are the signs of a damaged wiring harness?
- Several unrelated warning lights come on at once
- Gnawed wire, nesting material or droppings under the hood
- A no-start or stall that clears when you wiggle a connector
- Green or white crust inside a plug near the wheel well
- A melted or brittle section close to the exhaust or turbo
Should the harness be repaired or replaced?
It depends on how much of it is hurt and what the wires carry. A few chewed conductors in an open area can be spliced with solder or crimp sleeves, sealed with adhesive heat-shrink and re-wrapped. That keeps the factory routing and connectors.
Replacement makes sense when damage runs deep into the bundle, when many pins are corroded, or when heat has baked long stretches. We show you the photos and both options. If a new harness or module needs programming, that need is confirmed on the estimate before you approve anything.
Our wiring harness repair process
Step 1: Map the complaint
We list every symptom and pull codes with an OBD-II scan so we know which circuits to follow.
Step 2: Open and inspect
Covers, clips and tape come off along the suspect run so we can see and photograph the damage.
Step 3: Test each wire
Continuity and voltage drop checks show which conductors are broken, shorted or high in resistance.
Step 4: Repair to spec
Splices are staggered, soldered or crimped, sealed, and the bundle is re-wrapped and clipped on its original path.
Step 5: Verify
Codes are cleared, the system is retested and the car goes on a road test.
What's included in a wiring harness repair
Included on the work order
- 01Code scan and symptom list on the repair order
- 02Photos of the damaged section before repair
- 03Circuit testing of every affected wire
- 04Sealed splices or connector pin repair
- 05Re-wrap, loom and clip replacement along the repaired run
- 06Final retest and road test
Is harness damage a need-now repair?
Need now: call
- Wires that are shorting, smoking or blowing fuses
- Damage to circuits for the fuel pump, ignition or engine computer
- Chewed wiring that causes stalling in traffic
Need later: book
- A single cracked jacket with no exposed copper
- Corrosion on a comfort circuit such as a seat heater
- Old tape that is loose but still covering sound wires
How pricing and timing work
Harness work is priced by how far we have to open the car and how many circuits are involved. Finding the damage is diagnostic time; that fee is stated at the counter before testing and applies to approved related repair. The repair itself is on a written estimate, and if we find more damage we stop and call you. AAA members get 10% off parts and labor, up to $75, with the card at time of service. A short splice may be done in a day when the board allows; a full harness depends on parts.
Aftercare after harness work
Park away from ivy and stored feed to discourage rodents. If a warning light returns, call (909) 608-7699 and we will look at the same run first. Our electrical short circuit repair page covers what to do if a fuse blows again.
Frequently asked questions
Will my insurance cover rodent damage to wiring?
Some policies do. We document the damage with photos and a written estimate you can send your insurer. Call your carrier before approving work if you plan to file.
Can you just tape the chewed wires?
Tape alone lets moisture in and slips in desert heat. We splice each conductor, seal it with adhesive heat-shrink and then wrap the bundle, so the repair holds up to engine heat and vibration.
How do I know which wires are damaged if they look fine?
Some breaks hide inside the jacket. A voltage drop test with the circuit working shows resistance that eyes cannot see, which is why we test before we cut. See electrical system testing for how that works.