Greg Mathieu

• Diagnosed and replaced high voltage batteries in the GM EV vehicles : the GMC Hummer and Chevrolet Bolt. Failures diagnosed were internal open fuses, low cell voltage, and sometimes loss of isolation. NOTE; the newer GMC Hummer's and Chevy Bolt use the Ultium high voltage battery which at this time GM does allow any internal service.
• Diagnosed external high voltage battery concerns regarding the GMC Hummer, GMC Sierra, and the Chevy Silverado work truck. The repairer's made were battery coolant heater control module replacement and loss of isolation in the HVAC system which led to A/C compressor replacement along with a complete flush of the A/C system.
• Diagnosed and made internal repair's to the high voltage battery in the Chevrolet Bolt replacing battery sections and relay blocks. Failures diagnosed were low cell voltage in a battery section and pre-charge relay taking too long keeping the high voltage contactor's open.
• Diagnosed and replaced high voltage battery sections in the GM Chevy Volt along with other components in the Chevy volt high voltage battery including but not limited to, battery energy control module, high voltage battery coolant pump, high voltage battery relay block assembly, and the battery cell sensing modules.
• Diagnosed and made external high voltage battery repairer's for the Chevy Volt ; repairer's made were high voltage battery service disconnect replacement, battery heater coolant heater control module replacement, and power electronics coolant pump replacement.
• Diagnosed and replaced major components in the Chevy Volt transaxle and or drive unit assembly : rotor bearings, rotors, motor position sensors, case cover assemblies, and one time replaced a clutch.
• Diagnosed and repaired GM parallel hybrid trucks which included torque dampener plus stator replacement and occasionally the three Panasonic batteries wired in series.
• Diagnosed and made repair's to the drive unit in the Chevy Bolt : power inverter module replacement or loss of isolation within the drive unit itself which led to drive unit replacement.
• Diagnosed and repaired GM E assist vehicles : replaced generator control modules and at times the two sixty volt A/C batteries.
• Diagnosed and repaired the GM two mode hybrid trucks (Chevy Tahoe) ; repairer's made were high voltage cable replacement, power inverter module replacement, battery service disconnect, and internal high voltage battery relays.
• Primary shop foreman working with an assistant shop foreman. The assistant shop foreman dispatched jobs to other technicians and my role was to assist in diagnosing : (electrical testing, road testing with assigned technician to duplicate customer concern, locate any specialized tools and or equipment needed to repair the vehicle), and coordinate with the assigned service advisor an estimated time needed to repair vehicle.
• Worked with GM field service engineering on vehicles sold at our dealer, serviced at our dealer, or serviced at other dealer's to help prevent potential customer buy backs. These were vehicles with repeat concerns along with multiple repair attempts.
• Worked with a Raytheon representative on several occasions with claims of spontaneous air bag deployment whereas owner claimed loosing control of their vehicle resulting in a crash. The data collected and reviewed from the vehicle and at the site of said crash proved it was not equipment failure.
• Conducted routine maintenance checks, services, and identified any potential issues before they escalated into major repairs.
• Collaborated with service advisors to ensure accurate communication of repair status to customers.
• Utilized advanced diagnostic tools including but limited to a digital volt ohm meter, oscilloscope, and an insulation multi meter to diagnose concerns with customer's vehicle's.
• I made electrical repairer's from the start of employment till July 2026 which included wire to wire repair, terminal replacement, connector body replacement, re-stringing discontinued harness's from end to end (new terminal to new terminal), & complete harness replacement (engine, body, rear lamp , & forward lamp harness's) when repairing and wasn't cost effective.
• I made repair's to gasoline engines from start of employment til July 2026 (minor, major, & replacement). The minor repairer's were component replacement such as a coolant pump, generator, fuel pump (in tank & not in tank), turbo charger replacement, & replacing seals to repair an oil leak albeit some oil leak repairer's were more of a major repair.
• Stayed current on industry trends, attending training seminars regularly to update skills as new technologies emerged in automotive repair. This included informative monthly training from GM : monthly emerging issue videos informing technicians of new bulletin releases, arising concerns, new tools coming, & information regarding what vendors to get fluids, adhesive, or solvents from. There were also articles supplied by GM in Techlink magazine that I reviewed depending on the repair.
• Contributed to team success by sharing technical expertise during challenging diagnostic scenarios or difficult repairs.
• Boosted revenue through upselling additional services after careful evaluation of each client''s unique needs.
• Assisted in training junior technicians, sharing knowledge of advanced diagnostic techniques and best practices for quality repairs.
• Rebuilt transmissions, transfer cases, front differential assemblies, & rear differential assemblies from the start of my employment till July of 2026
• Repaired brakes, this included everything from component replacement (master cylinder, hydraulic or vacuum brake booster, rotors, drums, linings, & pads). I also replaced brake line assemblies and formed lines making dubble flare or 45 degree bubble end when the brake lines were no longer available through the manufacturer or aftermarket.
• Diagnosed and repaired anti lock systems along with traction control systems ; hub bearing replacement, brake control module replacement, wheel speed harness replacement, wiring repair, & connector replacement.
• Diagnosed safety and inflatable restraint systems. I replaced steering wheel coils, inflator modules, sensing + diagnostic module (referred to as the DERM on older GM vehicles), replaced connector position assurance retainers, & repaired connectors permissible by GM.
• Investigated customer complaints to identify cause of malfunctions. I would ride with customer's when we were unable to duplicate the concern.
• Coordinated with parts department to determine availability of necessary components.
• Explained maintenance and repair needs to customers and offered advice on preventative maintenance.
• Mentored junior technicians on best practices for repairs and customer service interactions.
• Kept service management aware of any upcoming possible concerns with customer if there was an indifference between the customer and the service consultant.

I was going into aviation maintenance during that time in life but as time went on, there were students that dropped out of the program. The dean of the college decided to put the aviation program on hold until enrollment increased, so I wound up taking a job at a freestanding Pontiac & GMC dealer with the intent to go back. I found out that the college decided not to continue the aviation program.