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Hey everyone, I’ve got a 99 C5 and none of the HVAC controls work, I have no heat or ac, and none of the blower settings work. I have no air blowing at all. All the buttons work but no output. I was also wondering how to flush the heater core, it might possibly be the cause of no heat. Any suggestions would help, thanks
Hey everyone, I’ve got a 99 C5 and none of the HVAC controls work, I have no heat or ac, and none of the blower settings work. I have no air blowing at all. All the buttons work but no output. I was also wondering how to flush the heater core, it might possibly be the cause of no heat. Any suggestions would help, thanks
Is there no air movement, or perhaps low movement out of all vents, including the defroster vents on the dash? Do you hear the blower motor try to change speed?
If the vacuum line to the HVAC switching valve is broken — a pretty common malady — the system doesn’t default to any single air path, but instead to all, including the defroster, doors, dash, and floor. Can make it hard to detect whether there is flow or not. Hand over the defroster vent is best check I’ve found.
Did you scan for any HVAC trouble codes ??...did you check fuses especially 27,18, and 51 in the IP fuseblock ??...27 and 51 are hot at all times and 18 is hot in the run position.
Did you scan for any HVAC trouble codes ??...did you check fuses especially 27,18, and 51 in the IP fuseblock ??...27 and 51 are hot at all times and 18 is hot in the run position.
Is there no air movement, or perhaps low movement out of all vents, including the defroster vents on the dash? Do you hear the blower motor try to change speed?
If the vacuum line to the HVAC switching valve is broken — a pretty common malady — the system doesn’t default to any single air path, but instead to all, including the defroster, doors, dash, and floor. Can make it hard to detect whether there is flow or not. Hand over the defroster vent is best check I’ve found.
I’ll check to see if there’s any air flow at all, if there is or isn’t what would be the next thing to look for?
When you wrote that all the buttons work, do you mean the control head display responds to temperature, mode, and blower speed ****/button changes?
Was everything with your hvac system working fine and then one day it just stopped working?
A plugged heater core should be pretty rare. What makes you think it is plugged?
yes that’s what I mean by the buttons working, as for the heater core, not too long ago it would blow air just very strangely, it would work on every setting but when you tried to increase or decrease fan it would take a couple minutes then it would change, and at that time when I did have air I had no heat and I’m just assuming it’s the heater core.
The only noise the blower makes is when I’m switching which vent air blows to, for example if I switched it from face to defrost it makes a little hiss sound nothing else
If the only current code is the 0363 so here is the factory flow chart to diagnose it…you will need a factory level scan tool or equivalent…it would be next to impossible to diagnose this for you over the computer…I would seek out professional help.
HVAC issues
