Paccar Control Relay Module Repair Service (Q21-1050)
Our Q21-1050 control door relay module repair service fixes driver-side power window, power mirror, door lock, and interior lighting faults common to Kenworth (T300, T660, T800, W900) and Peterbilt (386, 388, 389) trucks, without the cost of a full replacement. We diagnose, rebuild, and bench test every module, with a turnaround of 24 hours and no additional programming required.
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What we repair
Our technicians diagnose and rebuild Q21-1050 (including Q21-1050-001, Q21-1050-002, and Q211050) driver side door control relay modules using professional grade diagnostic equipment and high quality replacement components. We target the internal relay contacts, circuit board connections, and solder joints that most commonly fail with age, moisture, and vibration:
- Driver or passenger windows failing to operate from the driver master switch
- Power door lock switches unresponsive or operating intermittently
- Power mirror adjustment controls failing or freezing
- False "Door Ajar" warnings illuminated on the dashboard
- Interior dome lights failing to trigger when opening the driver door
Every module is bench tested before it ships to confirm all door lock, window driver circuit, mirror controls, and lighting functions perform to like-new specification.
Who it's for
This service is built for fleet managers, owner operators, and diesel technicians who need a Paccar truck's door electrical system working correctly again without paying dealership prices for a brand new control door relay module. It's a direct, cost effective alternative to buying an exchange unit, especially useful when nuisance door ajar warnings or non responsive locks are pulling a truck out of service for something that doesn't require a full module swap.
Fast turnaround, no reprogramming
We prioritize quick turnaround on every Q21-1050 repair to minimize downtime. Your repaired control door relay module ships back ready to install with no additional programming required, so you can plug it in and get back on the road. GoECM backs its remanufactured and repaired modules with a warranty, so you're covered after the repair, not just on installation day.
How It Works
Restoring your module has never been easier. GoECM's repair process is designed to minimize downtime while delivering exceptional quality and reliability. When you need a repair, fill out our Repair Service Form or follow the steps below.
That's it! Your module is back in action, and you're ready to hit the road. No need to thank us, just enjoy the ride.
If you have any questions or need assistance at any point our team is here to help. Don't hesitate to reach out—we're committed to ensuring your satisfaction every step of the way.
Inside the GoECM
Repair Process
Inside the GoECM
Repair Process
Repair Process
Let customers speak for us
Great service, you said exactly what you said you would do and it the repairs are working great.
Bob M.
Cummins CM570 ECM Repair Service
Excellent response time and service
Excellent response time and service . I will definitely use you guys again!
Donahue M.
GoECM
100% satisfied
The ECU repair fixed the no-start issue in my 1992 Honda Civic and, as a bonus, the check engine light is now "off" after being "on" continuously for the past two years. Service was fast -- the repaired ECU was back in my hands 9 days after shipping it to GoECM (and most of that time was the shipping itself).
Curtis L.
1992-96 Honda Civic ECM Repair Service
Sent it to them
Sent it to them , it was checked out found that it had no problems , i was called and told what was found and they shipped it back to me quickly. great company to do business with.
Michael L.
GoECM
2007-09 Dodge Cummins 6.7L CM2100A ECM 3970992
Nate D.
2007-09 Dodge Cummins 6.7L CM2100A ECM 3970992
have not ran road but cranks good no codes just
have not ran road but cranks good no codes just run about 1000 miles a year contact me 4 mounts i will give another review people at go ecm were very nice and helpful=
Frank M.
GoECM
TIPM Repair
They did great work and returned it in a very short time.
Charles M.
TIPM Repair Service for Chrysler Dodge Jeep
GREAT EXPERANCE
LOOK FORWARD TO DOING MORE BUISINESS WITH YOU.
Waters I.T.
International A26 ECM 7096443C3
I sent the a ECM from a caterpillar engine. It was giving me a lot of problems. I found them online and gave them a try.,after 5 days I got it back reinstalled it and everything worked fine. I was so thankful because I wasn’t a 100% positive that this was the problem.,
Dan F.
Caterpillar ECM Repair Service
Quick servcie and repaired TCM installed and
Quick servcie and repaired TCM installed and working great
Raymond R.
GoECM
Prompt service
ECM was not repairable, but the analysis was conducted quickly and results sent to me promptly
Gary M.
2009-11 Buick Enclave ECM Repair Service