When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Back at it again. After replacing both Blend Door Actuators, clearing trouble codes, checking Freon pressure, etc,etc I'm still getting slightly warmer air on driver's side. Tore apart everything AGAIN and started checking output voltages from the HVAC Head unit. Getting 13.2 volts power to each actuator with AC on. No vacuum leaks. Everything looks good except....I'm supposed to be getting anywhere from .4 to 5.0 volts when moving temp control **** from cold to hot. Voltage stays at a constant 5 regardless of which side temperature control **** i turn. Wonder if the HVAC head unit is bad ?
Which wire are you checking and seeing 5 volts ???....the YELLOW wires on my '01 anyway is the 5 volt signal from the HVAC control module....the light blue wire (L/H) and dark blue (R/H) is the signal return back to the module...it's a potensiometer...what is the voltage on these 2 wires moving the temp control **** from hot to cold ??
Are you checking your signal wire voltage with the connector plugged in ??...with the connector PLUGGED IN what voltage are you getting if you back probe pins A (signal) to B (ground) with your volt meter and moving the **** ?????...is your ground OK ???
When you have the actuators plugged in and operational, look at the actual HUB on the actuator and see if it turns the full range of it allowable travel. There is an index mark on the Air Box. See if both sides turn to the same positions when you go to full cold to full hot.
Remember. The passengers side can only change the drivers side master temp by 10% in either direction.
IF,, the actuators are actually moving the full range of their allowable movement, you could have a blend door issue that isn't allowing the drivers side to full close on the heat side.
Remove the actuator from the drivers side and manually move the damper shaft to fully cold and see if that solves the issue.
Are you checking your signal wire voltage with the connector plugged in ??...with the connector PLUGGED IN what voltage are you getting if you back probe pins A (signal) to B (ground) with your volt meter and moving the **** ?????...is your ground OK ???
No. . Checked it unplugged. I'm done roasting out in the driveway in this heat. I'll recheck everything while it's plugged in tomorrow morning and report back. Oh and BTW, checked continuity on the ground in the plug.It's good but I'm going directly to the neg. side of battery via a jumper for my volt meter.
When you have the actuators plugged in and operational, look at the actual HUB on the actuator and see if it turns the full range of it allowable travel. There is an index mark on the Air Box. See if both sides turn to the same positions when you go to full cold to full hot.
Remember. The passengers side can only change the drivers side master temp by 10% in either direction.
IF,, the actuators are actually moving the full range of their allowable movement, you could have a blend door issue that isn't allowing the drivers side to full close on the heat side.
Remove the actuator from the drivers side and manually move the damper shaft to fully cold and see if that solves the issue.
Bill
Bill, from what I can see from the opening of the main duct and a visual of the actuator indicator shaft outside of the actuator, both are moving to their full stop, both hot and cold. I even stuck my hand down the left side of the main duct and felt around the door seal. It was fully seated and no warm air was coming out around it.
Woops,, I misstated, the index marks are on the actuator. You should still be able to manually move the blend door shaft to full range hot and cold.
Bill
I don't know if this makes a difference but I did do the recalibration process after I installed both actuators. I'll pull the left Actuator off, manually close the door and see if it's any difference..... tomorrow morning. I'm done baking in this heat out in the driveway. 🤣
Good morning. Volt meter grounded to neg.side of battery, back probed left and right Actuators. Findings :. R actuator Power voltage 13.7.
Pin 9 reading, .471v cold with both temp controls at 60 degrees. No movement of right side actuator from hot to cold until I move the left side temperature control to 62 degrees. Right side actuator voltage Max is 3.3 volts.
Left side actuator readings: 13.7 volts at pin 5.
At pin 9 , .291v cold - 3.75v hot
No shorts to ground.
Bill, I disconnected and removed the left side actuator and was able to freely move the left side door inside the the housing. It fully seats and there is no binding. Using a digital temperature probe I have a 15 degree difference in temperature between right and left side, right side being the coldest
Here is the left side actuator showing positions hot to cold. I noticed that it drives past the cold position to make sure the door is fully seated.
This is in the HOT position.
From: Central PA. - - My AR15 identifies as a muzzleloader
I believe in the Beer Fairy
Have you tried measuring the voltage from ground where you're currently at (on the battery) to the signal grounds for the feedback? It's referred to in electronics as "ground bounce" and it indicates an inadequate ground. The PCM looks at that signal from the pot in the actuator as a door position and it's looking at voltage. Intuitively you think that means if there's 5V there, that means position X, but in truth, all it means is 5V ABOVE ground, which might be 3V if the ground is no good. So, keep in mind you're checking for a "potential difference" and while 5V is supposed to be minus 0V, that's not always the case. When it looks good but something isn't right, start checking the Voltage at ground also. Don't just assume it's 0VDC.
If you can move the blend door to the fully shut (cold) position by hand and you still have the 15 deg difference, the issue is INSIDE the air box! Maybe that blend door is damaged or not sealing properly. Looks to me like the electronic actuator is working perfectly.
Do you have access to a bore scope or a digital probe that you can snake down into the air box and inspect that blend door operation???? That's what I would do.
If you can move the blend door to the fully shut (cold) position by hand and you still have the 15 deg difference, the issue is INSIDE the air box! Maybe that blend door is damaged or not sealing properly. Looks to me like the electronic actuator is working perfectly.
Do you have access to a bore scope or a digital probe that you can snake down into the air box and inspect that blend door operation???? That's what I would do.
BC
Thinking way ahead of you...Removed the top of the air box as much as i can and checked both visually and by feel...sealed tight.
I have also been in contact with GM Tech and Corvette Guru Paul Koerner and giving him the same info I posted here. Here is his response : Your voltages are acceptable, however, you command from the HVAC control head is not accurate. You will most likely need a control head Edit
Hvac troubles continue.
. Checked it unplugged. I'm done roasting out in the driveway in this heat. I'll recheck everything while it's plugged in tomorrow morning and report back. Oh and BTW, checked continuity on the ground in the plug.It's good but I'm going directly to the neg. side of battery via a jumper for my volt meter.
