east302
I'm Awesome
The link to the 1997 PDFs isn’t on that first page of that thread - it’s in post #92. I think all of the years have been added by now, it’s just that no one can edit that first page to add the link.
AC Controls Fan not working on Hi
- Thread starter HoffmansHaven
- Start date
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HoffmansHaven
Newbie
Wow! Thank you! I found it. It never occurred to me to keep going through the thread. I probably won't dig through my truck again until fall. It's getting too hot here to mess with it. I have a lot of books now to help me.The link to the 1997 PDFs isn’t on that first page of that thread - it’s in post #92. I think all of the years have been added by now, it’s just that no one can edit that first page to add the link.
obs_dude-tx
Newbie
I experienced this same problem on the wife’s Suburban the last few weeks. I followed the wiring diagram provided on a previous post and got the test light out. My problem was the electrical connection after the firewall before the relay. There is a post in this forum that provides a step by step troubleshooting from the service manual that will help you narrow down the power issue with a test lamp.
blutge
Newbie
Hello All, new here. I have issues with my 1990 Chevy C1500 4.3L 2D HVAC system. There is a history, but cut to the chase and this is the current issue, the blower RUNS HIGH when turned On. Set the controller to Lo and Med, it run the same, HIGH SPEED. When switched to High the blower turns off. The resistor runs glow red hot, If the high blower relay is removed (purple wire) then the blower speed is low, resistor doesn't glow, but the same thing happens on the Lo, Med, switch settings, same speed no change, set on High the blower shuts off. The AC compressor, AC High, AC Low switches under the hood are NOT connected. Is this a short in the wire harness, a control panel short/burn out, or one of the three Blend Door Actuators. I've replace the wire harness from the pigtail plug, relays, and resistor. Looked at the back of the control panel it looked fine no carbon burn, did not look at the chip board yet, the actuator by the driver's side leg is working. Not sure about the other two, would faulty actuator cause this? Any help would be grateful, trying to get this fixed before finishing the R-12a to R134a AC upgrade. Thank You, B PS: the one fuse in the fuse box is good.
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AK49BWL
GMT400 Forever!
Actuators will NOT cause this issue. Have you replaced ANY of the relays? Switched connectors to the relays, see if the problem changes? It sounds like you might have a failed high-blower relay.
Relay positions per speed:
SPEED Relay 1 || Relay 2Off: OFF OFF --> Power in to relay 1, out to relay 2, dead ends at relay 2 because relay 2 is off.Low: ON ON -->Power in to relay 1, out to resistor pack, current flows through both resistors directly to blower - relay 2 is unused.Med: ON OFF --> Power in to relay 1, out to resistor pack, current flows through ONE resistor and then to relay 2, from relay 2 to blower.High: OFF ON --> Power in to relay 1, out to relay 2, from relay 2 direct to blower.So if Relay 2 isn't working, you'll have the same speed on Low and Med, nothing on High, and removing the relay entirely from the circuit causes the system to go to low speed because relay 2 (in its default off state) allows current to bypass the second resistor. The resistor glows because there's 1: no airflow over it, and 2: With relay 2 off, current is flowing through the one resistor - Low and Med are not running the blower at max, but technically Med.
For future reference, it's better to create a new thread for your problem
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