Electrical diagnosis is the work of tracing a fault through a circuit with a meter, a scope and a wiring diagram until you find exactly where the current stops or goes where it should not. AutoTech Clinic does this at 24100 Michigan Ave in Dearborn on foreign and domestic vehicles.
This is the work that other shops often send away. Corroded grounds, chafed harnesses and connectors full of salt are a large share of what we find, and they are common on vehicles that have spent many winters on Michigan roads.
- How Long
- From 1 hour for a simple circuit to several hours for an intermittent fault.
- Same Day
- Time frame confirmed before you leave the car.
- Vehicles
- Foreign and domestic, cars through trucks.
Signs You Need Electrical Diagnostics and Wiring
- A fuse that keeps blowing on the same circuit
- Accessories that work intermittently or only in certain weather
- The battery going flat when the car sits for a few days
- Several unrelated warning lights appearing together
- Dashboard lights flickering or gauges dropping out
- A burning or hot plastic smell from the dash or under the hood
What We Do
- 01
Reproduce the Fault
We get the fault to happen while we are watching. An intermittent problem that is not present cannot be diagnosed honestly, and we will tell you if we cannot make it appear.
- 02
Work From the Diagram
We use the manufacturer wiring diagram for your exact vehicle rather than a generic one, because connector numbering and ground locations vary by trim and year.
- 03
Voltage Drop Testing
Measuring voltage drop across a circuit under load finds high resistance that a simple continuity check will miss entirely.
- 04
Measure Parasitic Draw
For a battery that goes flat while parked, we measure the current the car draws asleep and pull fuses in sequence to isolate the circuit.
- 05
Repair Properly
We repair wiring with soldered or sealed connections and proper loom protection, not a twist and a piece of tape that will fail again next winter.
Why Grounds Cause So Many Strange Faults
Every circuit needs a path back to the battery, and most vehicles use the body as that path through ground points bolted to the chassis. When one of those points corrodes, current starts looking for another route, and it finds one through other circuits.
The result is the kind of fault that makes no sense: the dash lights dim when you use the turn signal, or the radio resets when you brake. One corroded ground can produce half a dozen unrelated symptoms, and cleaning it fixes all of them at once.
Parasitic Drain Takes Patience
When a battery goes flat while parked, something is staying awake. Modern vehicles take anywhere from twenty minutes to over an hour to put every module to sleep, so the measurement cannot be rushed.
Common culprits are aftermarket alarms and stereos, a glove box or trunk light switch, a failing door lock actuator, and modules that will not shut down because of a network fault. We find it by measurement rather than by replacing parts.
What Affects the Cost
We quote your vehicle specifically after inspecting it, because these are the things that move the number up or down:
- How intermittent the fault is and how long it takes to reproduce
- How many circuits and modules are involved
- Access to the harness section, especially inside the dash or in a door
- Whether a connector, a module or a full harness section needs replacing
- Aftermarket accessories such as alarms and stereos, which are a common source
Call (313) 277-7200 with your year, make and model and we will tell you what to expect before you come in.
Why AutoTech Clinic
AAA Approved
An inspected facility that has to meet AAA standards for equipment and training.
Photos First
You see what we found and approve the price before anything is taken apart.
Same-Day Service
Parts on hand for the vehicles we see most, so you are not waiting on a delivery.