Hummer Cars & Trucks - Recent Questions, Troubleshooting & Support


locksmith or auto service with a slimjim

Hummer Cars &... | Answered on Oct 13, 2019


No, but if your battery is already weak or failing, it could discharge enough to cause starting problems.

Hummer Cars &... | Answered on Oct 12, 2019


Not for that specific tail light. There may be a tail light fuse, but it would be for both sides.

Hummer Cars &... | Answered on Oct 10, 2019


Your best bet , take it to a qualified repair shop that knows what a wiring diagram is an how to use it along with a DVOM - digital volt ohmmeter to test electrical circuits .

Hummer Cars &... | Answered on Sep 25, 2019


Make sure the shift cable is properly moving the transmission into park.

2003 Hummer H2 | Answered on Sep 16, 2019


Acceleration issue can point to many potential problem, from a tune-up to emission sensors.

2003 Hummer H2 | Answered on Sep 16, 2019


That means your horn and electrical to the horn are good. You may have a bad clock spring under the steering wheel, or a bad switch. Don't forget to check the horn fuse. It may have a different circuit than the FOB.

2003 Hummer H2 | Answered on Aug 25, 2019


Pretty common problem with these. Here's a guide to learn how to fix GM instrument clusters yourself, I used it to fix mine and it worked great.How to guide for Silverado instrument cluster repair
Pretty common problem with these. Here's a guide to learn how to fix GM instrument clusters yourself, I used it to fix mine and it worked great.How to guide for H2 instrument cluster repair

2003 Hummer H2 | Answered on Aug 24, 2019


That's not how wiring diagrams are drawn. They're drawn by system, not location. See this post on how to get the diagram you're looking for

2003 Hummer H2 | Answered on Aug 24, 2019


Do you have an air bag light lit on the instrument cluster ? Do you have C.C. button's on the steering wheel , do they work ? If the alarm fob (as u call it ) Can make the horns sound , the relay is sending B+ voltage to the horns Don't know how your testing.
System Description
The horn system consists of the following components:
• Horn fuse
• Horn relay
• Horn switch
• Horn(s)
• Body Control Module (BCM)
System Operation
The vehicle horns are activated under the following conditions:
• The horn switch is depressed.
• The body control module (BCM) commands the horns on. The BCM commands the horns on under either of the following conditions:
- When the content theft deterrent system detects a vehicle intrusion. For further information, refer to Content Theft Deterrent (CTD) Description and Operation in Theft Deterrent.
- When the panic button is depressed on the remote control door lock transmitter. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry.
- When the OnStar® system is used to sound the horns, if equipped. For further information, refer to OnStar Description and Operation in Cellular Communications.
- When the keyless entry system is used to lock the vehicle, a horn chirp may sound to notify the driver that the vehicle has been locked. The notification feature may be enabled or disabled through personalization. For further information, refer to Keyless Entry System Description and Operation in Keyless Entry.

Circuit Operation
Battery positive voltage is applied at all times to the horn relay coil and the horn relay switch. Pressing the horn switch applies ground to the horn relay control circuit. The body control module BCM may also apply ground to the horn relay control circuit as described above. When the horn relay control circuit is grounded, the horn relay is energized and battery positive voltage is applied to the horn(s) through the horn control circuit. The horn(s) sound as long as ground is applied to the horn relay control circuit.

2003 Hummer H2 | Answered on Aug 24, 2019


Check the wires crossing the valve cover about midway ,under the crossover air pipe,,,especially if the plastic wire looms are deteriating ,,think the wires go to the egr not sure,,,check the wires for rub marks if any repair,,if the wire or wires are bad it will throw al kinds of crazy codes, delete codes see if it fixed it,,,also vacuum leaks will cause this issue to,,cracked rubber connectors and such
see YouTube vid. H3 hummer reduced power fix
taterhead3e

2006 Hummer H3 | Answered on Jul 21, 2019


Your best bet , have a qualified repair shop check it out . The windshield wipers / washer are controlled by the BCM - body control module .

Wiper/Washer System Description
The body control module (BCM) controls wiper motor low speed operation. The washer pump and high speed operation are controlled directly by the wiper/washer switch. The windshield wiper/washer switch supplies voltage on the signal circuits to the BCM for windshield wiper/washer operation. When WASH, MIST, DELAY, LOW, or HIGH is detected, the BCM energizes the wiper micro relay by suppling voltage to the relay coil. This allows battery voltage from the WIPER fuse to flow through the relay switched input then through the contacts and out the relay switched output to the wiper 2 relay switch contacts. Since the wiper 2 relay switch contacts are normally closed to the low speed circuit of the windshield wiper motor, the motor will operate at low speed.
The BCM is the gateway to all the modules on the vehicle , all are connected to a serial data network for sharing info.
Having a factory or some other type of a professional scan tool that can view BCM DTC'S - diagnostic trouble code's would be the first thing in the diagnostic procedure . If the BCM or wiper switch is causing a problem - shorted etc... it wont allow the BCM to message other modules , like the anti-theft system or engine computer , so the PCM/ECM - engine computer wont see message for the request for start . You need to know how the start system works also.
Circuit Description
Moving the ignition switch to the START position signals the body control module (BCM) that engine crank has been requested. The BCM verifies that theft is not active and sends a serial data message to the powertrain control module (PCM) requesting engine start. The BCM also energizes the RUN/CRANK RELAY. When the RUN/CRANK RELAY switch side closes, and the vehicle is in Park/Neutral or with the clutch fully depressed, if equipped, supply voltage is applied to the PCM CNTRL relay coil. The PCM verifies the transmission is in Park/Neutral or if the clutch is fully depressed, if equipped. The PCM will then ground the control circuit of the PCM CNTRL relay, closing the switch suppling voltage to the starter solenoid. On some vehicles the starter will continue to crank the engine with the key released until it starts, the crank command has timed out to prevent excessive heat build up in the starter circuitry or the PCM receives an engine run flag.
There is nothing your going to be able to do , nor should you try . So do yourself a favor an take it to a qualified repair shop.

Hummer Cars &... | Answered on Jul 16, 2019

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