bypassing the a/c thermo dial switch ?

[Tallbrad]

Got all new r12 and it was glorious for a few days there but now the temp sensor turn knob has stopped working, I understand I can bypass it by removing the center console cubby and turn knob and removing the switch.

Anyone have a photo - write up on this bypass ?

Or anyone have a write-up on adapting a new switch for a 79sc as I understand they dont sell the old switches anymore.. must retrofit a new one..

Many Thanks,

JB

[86 911 Targa]

Originally Posted by Tallbrad

Got all new r12 and it was glorious for a few days there but now the temp sensor turn knob has stopped working, I understand I can bypass it by removing the center console cubby and turn knob and removing the switch.

Anyone have a photo - write up on this bypass ?

Or anyone have a write-up on adapting a new switch for a 79sc as I understand they dont sell the old switches anymore.. must retrofit a new one..

Many Thanks,

JB

Email sent.

[kuehl]

The circuit is rather simple, two wires, so its in series.
Open the center console, locate the thermostat on the left (usually),
disconnect green and green/white wire from its terminals and connect
to a 'switch' (not much amperage). However forgetting turn off the switch
can cause other issues such as freezing the evaporator core or damaging a compressor.

Maybe you want to spend a little time trouble shooting the circuit, a decent schematic can be found here on PP. Replacement thermostat's are available and R&R is rather easy for DIY.

[Justin@Athens]

kuehl, I have done a you described; however I register no current at the green and green/white wires on the multimeter? what is my next step backwards?

[kuehl]

Originally Posted by Justin@Athens

kuehl, I have done a you described; however I register no current at the green and green/white wires on the multimeter? what is my next step backwards?

Did you turn on the fan speed switch on the right and then check it?

[Justin@Athens]

yes sir, got voltage there--fan speed shows varying voltages depending on pins selected. still nothing out of the green and green/white wires

[kuehl]

On the back of your fan speed switch's mating plug, the circuit for an 89 shows a green/white wire (which feeds the thermostat and condenser fan relay.. etc.) Check for voltage on the green/white wire's crimped terminal where it exits the switch plug when you have the switched turned on. You an review the schematic on a 89 on in the shop manual page 970-51.