Diagnostic Tips
Chasing an intermittent no-start.
Where seasoned techs start when the code list is empty.
Read moreLive specialists since 1994
The right advice, right away.
Our veteran specialists solve tough diagnostic problems live over the phone. Since 1994 we have helped independent shops fix the hard ones fast, so techs stop guessing and start billing.
- ✕Misdiagnosis
- ✕Parts Hanging
- ✕Research
- ✕Troubleshooting
Our Service
What you get when you call.
One phone number, four ways we help you close the ticket faster.
Live Specialist Calls
Talk to a real technician, not a bot or a message board.
Learn moreWiring Diagrams and TSBs
Fast access to service bulletins and factory diagrams.
Learn moreAll Makes and Models
Domestic, import, light truck, and diesel coverage.
Learn moreGM Radio Loc
Get radio unlock codes for GM vehicles in minutes.
Learn more
A specialist on the line in minutes.
How It Works
Five steps to a fix.
- 1
Call in.
- 2
Describe the vehicle and the problem.
- 3
Diagnose live with a specialist.
- 4
Get the fix and get back to work.
- 5
Call again anytime, no re-sign-up needed.
Trusted since 1997
The official diagnostic hotline for AC Delco.
Since 1997, Diagnostic Hotline has been the official diagnostic support line for AC Delco, part of General Motors. That is 29 years of continuous partnership, an endorsement we do not take lightly and one no competitor can match.
29 yrs
Official partner
GM
Endorsed hotline
1997
Trusted since
30+
Years helping shops
since 1994
30,000+
Shops served
across 50 states and Canada
630,000+
Diagnostic calls answered
$18M
Saved in unnecessary parts
for independent shops
50+
States and Canada
Trusted from coast to coast
150+
Years of underhood expertise
on the line
Voices from the bay
Shops trust the hotline.
Real quotes from independent shop owners across North America.
“Thank you for helping me get through that wiring problem. You are very knowledgeable and you have the patience to explain things properly.”
“We have been using Diagnostic Hotline since 1994. We are able to make more money because we eliminate lost time on misdiagnosis and needless parts hanging.”
“I call Diagnostic Hotline for advice on every tough job. Sometimes just a different approach makes all the difference. Nobody can know it all.”
Resources we tap into
OE Factory Service Manuals
Mitchell on Demand
Motor and Alldata Information
Industry Databases
Helpful Tips
