TTS Question - 82 SC

[AaronLPDX]

Hi, I did the heater backdate today on my new-to-me 82 SC (huge, huge thanks to everyone who's posted about it here - so helpful! I also can't get over how much better the engine compartment looks now) and I noticed a weird connection as I was buttoning everything back up. I'm fairly new to aircooled 911 goodness, so I had to look up the function of this sensor and went down the rabbit hole of reading about the thermo-time sensor and its function in cold start scenarios.

My question: Why would a PO (or their mechanic) have hooked up only the red/black wire and cut the yellow one? My car starts great, cold or not. It has been quite warm here in Portland since I got it, so I haven't experienced a truly "cold" start yet, but I wasn't sure if there was a reason for bypassing some part of this switch. Also, I'm not even sure if the red/black wire is hooked up correctly (picture below) Thanks!

[boyt911sc]

The TTS has two (2) round terminals namely:

• Smaller round terminal —————Yellow wire.
• Bigger round terminal——————Red wire with black stripe.

Yellow wire supplies power and red wire with black stripe is ground (-). There is no ground contact (open) when temperature is above 113°F. Test the TTS if it is good or defective. The picture you posted shows correct wires connection/installation.

Tony

[AaronLPDX]

Tony, thanks for the reply. Sorry if the picture wasn’t clear. The yellow wire is cut with no connector on the end of it. Only the red/black is connected to the top terminal of the TTS.

[mike sampsel]

Originally Posted by AaronLPDX

Tony, thanks for the reply. Sorry if the picture wasn’t clear. The yellow wire is cut with no connector on the end of it. Only the red/black is connected to the top terminal of the TTS.

No yellow wire means the CSV will not energize on a cold start. The TTS allows for current flow by making a ground until the TTS heats up and causes an open circuit. No idea why the PO decided to not allow the CSV to operate.

[mike sampsel]

Originally Posted by boyt911sc

The TTS has two (2) round terminals namely:

• Smaller round terminal —————Yellow wire.
• Bigger round terminal——————Red wire with black stripe.

Yellow wire supplies power and red wire with black stripe is ground (-). There is no ground contact (open) when temperature is below 113°F. Test the TTS if it is good or defective. The picture you posted shows correct wires connection/installation.

Tony

Isn't the circuit open when the temperature is above 113 deg F?

[boyt911sc]

Originally Posted by mike sampsel

Isn't the circuit open when the temperature is above 113 deg F?

Mike,

That’s a typo. I corrected the above post. Open when warmed up and close when cold.

Tony

[boyt911sc]

Originally Posted by AaronLPDX

Aaron,

Are we referring to the same picture? The picture you posted shows two (2) wires with connectors to the TTS. Is this the picture of your motor? Please advise. Thanks.

Tony

[AaronLPDX]

Hi Tony, it is my motor. The yellow wire is just sitting on top of the red/black one and not connected to anything. It’s just an unfortunate angle for the photo.

[boyt911sc]

Aaron,

If you need help testing and evaluating your TTS , send it to me with a RSL (return shipping label) preferably a UPS. I have a TTS tester that could test it in seconds and it’s FREE testing. PM me if you are interested.

Tony

[AaronLPDX]

Thanks, Tony. I may take you up on that generous offer. I think my first step will be to reattach a connector to the yellow wire and make sure the sensor is connected properly. Then, I’ll take it from there.

[boyt911sc]

Originally Posted by AaronLPDX

Thanks, Tony. I may take you up on that generous offer. I think my first step will be to reattach a connector to the yellow wire and make sure the sensor is connected properly. Then, I’ll take it from there.

The first thing you should do is to test and confirm that the TTS is good and working. Not the other way around. Do it the way you want it and keep us posted.





Tony