I removed my dash and auto AC control to install LEDs as many of the bulbs were inop. I installed all and everything works as it should except the dash indicator for the cruise control stays green on the dash. The cruise control works as it should but the brake and on off button do not affect the green color of the lamp. I tried the instrument panel reset but could not get the instrument panel to "reset". Look on-line and could not find a post that included this fault. Anyone have an idea how to diagnose or fix this? Thanks
2004 Tahoe ZR1 cruise light stays green
- Thread starter BMS
- Start date
christo829
Member
The first thing that comes to mind is whether the polarity is correct on the
LED? I've had other projects where an LED will stay lit if the polarity is reversed, but that was
in other electronics besides the instrument panel. Hopefully some of the more
LED mod savvy members here will chime in.
Good Luck!
Chris
LED? I've had other projects where an LED will stay lit if the polarity is reversed, but that was
in other electronics besides the instrument panel. Hopefully some of the more
LED mod savvy members here will chime in.
Good Luck!
Chris
I should clarify that I didn't replace any of the sensor lights, just the 9 or so "backlighting" bulbs. The small sensor LED lights were all operational. You are correct on polarity and I have a "polarity" chart for the dash lights that I followed. The sensor LEDs all work fine except the constantly green cruise control light.
Welcome to GMT Nation...
The Cruise Control Circuitry is intimately involved with the Brake Pedal Switch mounted on the Brake Pedal Armature Rotation Point (held in with a Spring Clip and basically ... an uncomfortable PITA to get to and R&R):
So as a likely suspect when things go sideways, examine your Wiring Diagrams to trace out what happens whenever the Brake Pedal gets *tapped* to easily disengage the CC System for Safety Concerns.
The Non-OEM part listed below is an example of what is available via Amazon and from RockAuto, as well:
If you determine THIS component is the problem, check on YouTube for Generic GM Brake Pedal Switch R&R Instructions... and mind where that Retention *Clip* might Fly Off whenever removing it or installing it after plugging in the Harness Connector.
The Cruise Control Circuitry is intimately involved with the Brake Pedal Switch mounted on the Brake Pedal Armature Rotation Point (held in with a Spring Clip and basically ... an uncomfortable PITA to get to and R&R):
So as a likely suspect when things go sideways, examine your Wiring Diagrams to trace out what happens whenever the Brake Pedal gets *tapped* to easily disengage the CC System for Safety Concerns.
The Non-OEM part listed below is an example of what is available via Amazon and from RockAuto, as well:
If you determine THIS component is the problem, check on YouTube for Generic GM Brake Pedal Switch R&R Instructions... and mind where that Retention *Clip* might Fly Off whenever removing it or installing it after plugging in the Harness Connector.
Last edited:
If you have access to a scan app like Torque Pro there are two custom PID's that you might try to query to determine the system status of cruise control:
| Long Name | Mode&PID | Formula | Min | Max | Header | Scale |
| Cruise Control Active (Pid 1100 Bit 7) | 221100 | Lookup(BIT(A:7): :1='Active':0='OFF') | 0 | 100 | 6C10F1 | x1 |
| Cruise Control On/Off Switch (bit 4) | 221116 | Lookup(Bit(A:4)::0='OFF':1='ON') | 0 | 1 | 6C10F1 | x1 |
Last edited:
how did you try to reset the IP?
do you have way to monitor data bus messaging to see if the IP receives an "off" message?
Since the system is basically working, I would suspect a "leaky" circuit. With the key off, do an impedance check (to ground) on the "negative" side (cathode) of the led. It should be really high / open.
do you have way to monitor data bus messaging to see if the IP receives an "off" message?
Since the system is basically working, I would suspect a "leaky" circuit. With the key off, do an impedance check (to ground) on the "negative" side (cathode) of the led. It should be really high / open.
Last edited:
For a 2004 Tahoe it 'looks' like the cruise indicator was already an LED??
See diagram #2, "indicators", upper left.
See diagram #2, "indicators", upper left.
Electrical Diagrams — 2004 Chevy Truck Tahoe 4WD V8-5.3L VIN T Service Manual | Operation CHARM
Detailed repair manual for the 2004 Chevy Truck Tahoe 4WD V8-5.3L VIN T.
charm.li
then it becomes a question of what type of led was used? or maybe: why was the existing replaced?
Blckshdw
Moderator
I put the tech 2 on it and couldn't find any faults. Everything works as it should. Looked at the wiring diagram in SM and it disappears into a block called IPC for instrument panel cluster with no detail. Since, there is an action direct directly associated with this, I have to assume that I induced the fault when working on the IPC. When I get time, I will take it out again and see if I can't trace the board connections/routes associated with the panel. BTW: I have had this Tahoe since new, has 200k miles, runs and looks like new, and I have never had any major problems with it. I love this era of Tahoes! I had a Bronco for 10 years prior to getting this and there is no comparison in ride, comfort, reliability!
For answers to above. Only replaced the 9 or so incandescent lamps. Did not attempt to replace LED warning indicators. LED bulb replacements work as they should. LEDs were used to replace all backlight lamps as several were burned out. Replaced them once before with incandescent bulbs and they don't seem to last so I just replaced them all with LEDs. I didn't see the wiring diagram above. Much more detailed than what I have. Thanks to all for input. Will let you know what happens. Might be a week or two!
For answers to above. Only replaced the 9 or so incandescent lamps. Did not attempt to replace LED warning indicators. LED bulb replacements work as they should. LEDs were used to replace all backlight lamps as several were burned out. Replaced them once before with incandescent bulbs and they don't seem to last so I just replaced them all with LEDs. I didn't see the wiring diagram above. Much more detailed than what I have. Thanks to all for input. Will let you know what happens. Might be a week or two!
Last edited:
I think what you need to do is monitor the bus messages for the activation command which turns on the light and then the deactivation command to turn it off. IF those exist for the IPC, then you likely have an internal IPC issue either caused by your bulb work or a component failure. The impedance measurement will provide you with info as to whether there is a "pure short" to ground or some other type of "leakage" that could be related to the bulb "transition"... circuits designed for "resistive loads" some times don't consider other types of loads being introduced. Hopefully, your further inspection of the IPC board will provide the answer.
FWIW, the functional 3 byte header to be sent for activating or deactivating the cruise indicator with an OBD adapter and serial terminal is "8A EA F1".
"A0 8C 00" turns on the cruise indicator.
"20 8C 00" turns off the cruise indicator.
Seen here at about 16 seconds into the video...
"A0 8C 00" turns on the cruise indicator.
"20 8C 00" turns off the cruise indicator.
Seen here at about 16 seconds into the video...