Complete Car Electrical Service in Ambattur, Chennai
Car electrical service at GM covers testing and repair of the battery, alternator, starter motor, wiring, fuses, relays and the A/C electrical circuit, for all car brands, at the Kallikuppam (Ambattur) workshop. We test and trace the fault first, then quote the repair in writing for your approval before any part is replaced.
Faults that look alike can have different causes: a car that will not start may have a weak battery, a corroded earth connection or a worn starter. The battery, alternator, starter and wiring checks are part of the free 30-point A/C and electrical checkup.
Reviewed by G.M. Manigandan, founder and lead technician · Last reviewed
Is the electrical check part of the free 30-point checkup?
The free 30-point A/C and electrical checkup includes the battery, alternator, starter and wiring checks. We diagnose before we replace; any repair is quoted in writing for your approval.
Book the free checkup Book on WhatsAppWhy is my car AC not working even after gas was refilled?
If your car AC was recharged with refrigerant but still doesn't cool, the fault is often electrical: the compressor never receives the signal or the power to run, so fresh gas changes nothing. A seized compressor or a blockage can cause the same symptom, which is why we test the circuit before recommending a part. The full A/C not cooling diagnosis covers the gas, mechanical and electrical sides together.
Common AC electrical faults we find and fix:
- Failed AC compressor relay, prevents compressor from receiving power
- Blown AC fuse, easy to replace when the right fuse is identified
- Faulty AC pressure switch, incorrectly signals low pressure, blocking compressor
- Failed blower motor or resistor, no airflow despite AC being on
- Wiring harness damage, rodent damage, heat damage, chafed insulation
- AC control module fault, signals not sent or received correctly
Call +91 88893 60888, we diagnose the exact electrical fault before recommending any repair.
Diagnosis before parts: the inspection and testing scope is confirmed before work starts. If repair is recommended, GM explains the test result, parts, labour and written estimate for your approval.What does car electrical service include?
AC Electrical Circuit Diagnosis
Full diagnosis of the AC electrical system, compressor relay, pressure switches, blower motor circuit, AC control module, wiring continuity testing.
Battery & Alternator Testing
Battery load testing, cold cranking amp verification, alternator output voltage and current testing. Heat shortens battery life, so we test the battery before it leaves you stranded. See battery replacement and alternator repair.
Wiring & Fuse Diagnosis
Systematic tracing of wiring faults, shorts, open circuits, rodent damage, corroded connectors, blown fuses and their root causes. We find the fault, not just replace the fuse.
Which electrical symptoms do we diagnose?
AC compressor not engaging / clutch not clicking
The compressor clutch not engaging is often electrical, failed relay, blown fuse, faulty pressure switch, or low voltage. Our technicians test each component in sequence to identify the exact failure point before any parts are replaced.Blower fan not working or working on only some speeds
A fan that works on high but not low speeds usually indicates a failed blower resistor (common in Chennai's heat). A completely dead blower points to a failed motor, fuse, or relay. We test and replace only the faulty component.Car battery draining overnight
Parasitic battery drain, where something stays on after the car is switched off, requires systematic current draw testing on each circuit. We use a clamp meter to identify the circuit drawing abnormal current, then trace it to the specific component. More on battery drain diagnosis.AC working intermittently, cooling on and off
Intermittent AC faults are the hardest to diagnose, they disappear when you bring the car in. Our technicians know the common intermittent failure patterns: heat-sensitive relays, corroded connectors that make contact only sometimes, and pressure switch faults that cut out under load.Rat bite / rodent damage to car wiring
Rat and rodent bites on wiring are a very common cause of sudden electrical faults in Chennai: AC cutting out, warning lights, a dead sensor, or a circuit that stops working overnight. We trace the chewed wiring harness, repair or replace the damaged section, restore proper insulation and connectors, and test the circuit end to end. We fix the actual bitten wiring, not just clear the fault code.Function keys / buttons / switches not working
Dashboard buttons, AC control panel keys, power window switches, wiper or light controls that stop responding are usually a failed switch, a broken connector, or a wiring fault behind the panel. We test each control, find whether the fault is the switch itself or the circuit feeding it, and repair or replace only the faulty part so every function key works again.The GM Diagnostic Difference
We don't guess and replace parts hoping to fix the fault. Every diagnosis starts with systematic testing using proper tools, multimeters, circuit testers, and manufacturer wiring diagrams. You only pay for what actually needs replacing.
Diagnosis-first · written estimate before work
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Electrical Symptom Quick Reference
| Symptom | Possible cause | Recommended check |
|---|---|---|
| Battery warning light stays on while engine runs | Alternator not charging, worn brushes, failed diode, loose or corroded connection | Alternator output voltage test at idle and higher RPM |
| Car cranks slowly or does not start | Weak or discharged battery, corroded terminals, poor earth connection, starter fault | Battery load test and terminal/earth inspection |
| AC blows warm air though gas level is normal | Failed compressor relay, blown AC fuse, faulty pressure switch, wiring fault | AC electrical circuit and relay test |
| Function keys, switches or dashboard buttons stop responding | Failed switch, broken connector, wiring fault behind the panel | Continuity test of the switch and its wiring |
| Several electrical faults appear suddenly together | Rodent-damaged wiring harness, chafed insulation, blown fuse | Visual harness inspection and circuit continuity test |
| Battery drains overnight with no visible cause | Parasitic current draw from a stuck-on circuit or faulty component | Clamp-meter parasitic draw test with circuits isolated one by one |
| Blower fan works on some speeds only | Failed blower resistor or partially failed motor | Blower circuit and resistor test at each speed |
This table lists common patterns for reference. It does not diagnose your specific vehicle, a technician confirms the actual cause after inspection. For warning lights and stored fault codes, see car scanner diagnostics.
What affects car electrical repair cost?
The cost of auto electrical repair depends on the vehicle model, the brand and specification of the replacement part needed, how much labour is required to access and test the affected circuit, whether other components were damaged by the original fault, and parts availability for that specific car. It also depends on whether the failure is in the component itself, a relay, sensor or motor, or in the wiring feeding it, since wiring faults typically take more diagnostic time. An estimate is given only after the fault is diagnosed.
Diagnose Your Car's Electrical Fault Today
Stop guessing and swapping parts. At GM Car A/C Service, we use systematic diagnostic methods to find the exact fault, then repair only what's needed.
Call +91 88893 60888: Book Diagnosis WhatsApp us Book Appointment12A, Gangai Amman Kovil Street, Kallikuppam, Ambattur, Chennai 600053 · Mon–Sat 10AM–8PM
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Four steps, in this order, every time
Diagnosis-first is the whole method: measure, write it down, then price it. It is also why every job, gas filling included, is quoted in writing after the checkup.
We test before we quote
The free 30-point A/C and electrical checkup runs first, 15 to 35 minutes, with a written report of what was measured.
You get the estimate in writing
The report says what was found. Gas filling, like everything else, is quoted in writing after the checkup, and nothing starts until you approve it.
No work starts until you approve
Nothing is opened up or replaced before you say yes to the estimate. If the diagnosis changes the scope, you hear about it first.
Repaired, then checked again
The approved work is done and the car is checked again before handover.
Frequently asked questions
Why is my car AC not working even after gas filling?
If your car AC was recharged but still doesn't work, the fault is likely electrical. Common causes include a failed AC compressor relay, a blown fuse in the AC circuit, a faulty AC pressure switch, a failed blower motor, or a wiring fault. GM Car A/C Service diagnoses AC electrical faults systematically, our technicians use multimeters and circuit testers to find the exact failed component.
Can a weak battery cause car AC problems?
Yes. A weak or failing battery causes voltage drop that affects AC compressor engagement, blower motor speed, and control module function. In Chennai's heat, batteries degrade faster than in cooler climates. If your AC shows intermittent or irregular behaviour, a battery health test is part of our diagnostic process.
How long does auto electrical diagnosis take?
A focused auto electrical diagnosis at GM Car A/C Service typically takes 30–90 minutes, depending on fault complexity. Simple relay or fuse repairs are short jobs. Complex wiring fault tracing may take longer. We provide a clear timeline and estimate before any repair work begins.
Do you repair rat bite / rodent damage to car wiring in Chennai?
Yes. Rat and rodent bites on wiring are a very common cause of sudden car electrical faults in Chennai: AC cutting out, warning lights, dead sensors, or a circuit that stops working overnight. GM Car A/C Service traces the chewed wiring harness, repairs or replaces the damaged section, restores proper insulation and connectors, and tests the circuit end to end. We fix the actual bitten wiring, not just clear the fault code.
What tools do you use to diagnose electrical faults?
GM Car A/C Service uses multimeters, clamp meters for current-draw testing, circuit testers and, where relevant, an OBD scanner to read stored fault codes. Wiring diagrams for the specific make and model are used to trace circuits accurately rather than guessing at components.
Can electrical faults come back after repair?
A properly diagnosed and repaired electrical fault should not recur from the same cause. If a similar symptom returns, it is usually a different component in the same circuit, bring the vehicle back so the circuit can be re-tested rather than assuming the earlier repair failed.
Do you service electric vehicles (EVs)?
We service the AC and general electrical systems of electric and hybrid vehicles, cabin cooling, wiring and diagnostics. High-voltage battery and drivetrain work needs the vehicle manufacturer's own service network. Call +91 88893 60888 to confirm we can help with your EV model.
What is the cost of auto electrical service in Chennai?
We do not quote an electrical repair before testing, because the cost depends on which part has failed: a fuse or relay is a small job, while tracing a wiring fault or replacing a module takes more labour and parts. The free 30-point A/C and electrical checkup finds the fault, and the repair is then quoted in writing for your approval before any work starts. Call +91 88893 60888 to book the checkup.
My car's function keys / buttons / switches are not working, can you fix it?
Yes. Dashboard buttons, AC panel keys, power window switches, wiper and light controls that stop responding are usually a failed switch, broken connector, or wiring fault behind the panel. We test each control, find whether the switch or the circuit is at fault, and repair or replace only the faulty part so every function key works again.
Related pages and areas
Tell us what the car is doing
Pick a day and a time and send a slot request. We confirm it by phone or WhatsApp in workshop hours. The 30-point A/C and electrical checkup is free, takes 15 to 35 minutes and comes with a written report. Nothing is charged and no work starts without your approval.
Customer Service · Individual car owners. Mon–Sat 10:00 AM – 8:00 PM, Sunday closed. Prefer not to call? The form takes about 30 seconds.
Illustrative image. Not a photograph of GM premises, staff or a customer vehicle.