No Heat

You could have any number of issues.

I had a similar issue just after i replaced my heater core in my 84T with the digital climate control. After lots of headscratching, reinstallation and even borrowing a FLiR thermal camera from work
it turned out that the new core had a air pocket that was keeping the hot water from flowing through it.

Not sure if this is the cause of your issue, But i solved it by burping the coolant system until the air pocket came out using a Lisle yellow funnel.

It's also quite possible you have a stuck vent actuator (on the back of the door assembly) OR a failed servo (drivers footwell, top right) that directs vacuum to that particular actuator when the control unit tells it to open OR a failed circuit on the control unit that is telling the servo to open and direct vacuum to the actuator. This path of troubleshooting is best accomplished with the dash removed.

It's also quite possible that you have a stuck diverter valve. Without vacuum it stays open, allowing hot water to flow through the heater core. When it is closed, the heater core is bypassed. It's located on the firewall to the right of the battery. You should be able to actuate the plunger by hand, though with all the stock wiring and stuff in the way it can be difficult to get to.

Thanks for the reply, I replaced the heater core over 25 years ago, the mechanic that did the job (Z Expert in Los Angeles) knows these cars super well and had a place that significantly upgraded the units so it was a one tiime replacement, so I am pretty sure that isn't my problem. Also no coolant on passenger floor like last time. The air redirects into the correct places, I still think it was a huge miss by not having the ability to direct air exactly where you want it, but putting on Defrost did fine and also when it was cold the air was sent to lower area as it should.

I will try to see about the plunger and see if I can figure that out. If not I plan to take the car to LA after it warms up for a few other smal gremlins and I know Z Expert can figure it out. Seems like htat must be the issue, I checked the coolant level and it is to the top.

The stock control head has a cycling diagnostic mode for exactly this situation, doesn't it? Unless the 1984 climate control was laid out significantly differently.

I seem to remember something about that, I think the control modules look about the same on all the GLL with digital. Do you remember how to do that?

Xenon has a writeup: http://xenonzcar.com/z31/Automaticcl…ntroldiag.html

Geez, shorting out two wires, not thinking that I am going to do that. I don't think this is an issue with the controller as I can move the airlow around from defrost to heat and to AC, the issue is getting the heat to kick in. I htink it must be the part described above.