HELP, Any idea what my next step should be?

[chris_d]

Hi folks,

First post but long time lurker

I own a 2000 LS V6 and have been experiencing the typical faulty DCCV symptoms of uneven temp control with more heat than cold air. Well yesterday I spent all day busting my knuckles replacing this valve. What a job! After all that it's still doing the same exact thing as before. If it's set at 65 degrees (on both sides) I get a blast of hot air on the driver's side and luke warm air on the passenger side. I don't believe it's my AC because when I crank it down to 60 degrees, it will use the bypass door and blow cool air like it's suppose to. Plus every AC component was replaced earlier this year do to compressor issues .

Any ideas on what else could be wrong? I have considered pulling the plug to the new DCCV and connecting it to the old one, just to see if I can hear the solenoids engaging. Other than this I have no clue on what to do next. It also makes me sick that I may of spent $175 for a part that wasn't even needed.

Thanks in advance!

 

[joegr]

It sounds like power is not getting to the driver's side valve. (The valve closes when power is applied, and opens when there is no power. Open = hot)

This data is for gen II, but I think that the valve is the same for gen I or gen II.
http://deneau.info/ls/s6x~us~en~file=s6xc0003.htm~gen~ref.htm#PS2-J

You need to do the testing at step J2. Note that the chart is incorrect when it says to install a new DATC if the voltage is not present. If voltage is not present (I bet that it isn't), then you need to trace the wiring all the way back to the DATC and check for a broken wire or a short anywhere along the way. I'm sorry that I can't give you the pin numbers to look at at the DATC, those are different for gen I. Maybe someone else can supply that.

 

[chris_d]

Duplicate post

 

[chris_d]

Duplicate post

 

[chris_d]

Thanks for the reply this was a big help.

Looking at the diagram, the way I understand it is that the center pin on the plug is always hot. When DATC calls for cold air it will ground one of the outside pins depending on which side called for it ie being either the pass or driver side. Once the pin is grounded the solenoid engages which then will block the supply of coolant to the heater coils. Does this sound about right?

 

[joegr]

Thanks for the reply this was a big help.

Looking at the diagram, the way I understand it is that the center pin on the plug is always hot. When DATC calls for cold air it will ground one of the outside pins depending on which side called for it ie being either the pass or driver side. Once the pin is grounded the solenoid engages which then will block the supply of coolant to the heater coils. Does this sound about right?

That appears to be what it does, but I haven't actually scoped it to see for sure. For temperatures between full-heat and no-heat, it pulses each valve very quickly - so fast that instead of opening and closing, it stays somewhere in between.

 

[joegr]

This helps a lot. I can't believe the wiring to the plug has changed to much for the GEN 2.
...

I think that the plug at the DCCV is the same. The connectors at the DATC are somewhat different (from gen II).

 

[chris_d]

I know it has been a while, but I just started to get around to troubleshooting this problem some more.

To test the DCCV....I unplugged DCCV and jumper wired it so that it would energize both solenoids thus making both valves go fully close. Sure enough the DCCV is working like its suppose to (I now have full AC on both sides). I wanted to elimate the DCCV for sure even even though it was apparant that the DCCV was most likely functioning because I only had 10 volts going to the driver side solenoid. At least the great news is that it isn't my AC and it's not my brand new DCCV valve that I just installed!

Ok so now on to the next step. I guess I need to troubleshoot those darn cabin sensors. From reading I guess the best way to do this is to swap the driver side sensors with the passenger side sensors.

Question: Does anyone know where and how to get to those darn cabing sensors on a GEN 1 LS? Any advice would really be appreciated.