Just to verify. Is A/C D8050 the correct switch for a 1971 Cutlass 350? Idiot light, no gages. The specs refer to it as Normally Open. This sounds wrong. It should be N/C if tested on the workbench. On the other hand it's N/O in place w/ the engine running. The one on the car was working fine (Lamp lit w/ key on engine off) but now quit. No continuity through the switch engine off. I want to order the correct one.

 

I replaced mine in my '71 CS 350 cid w/ D8050 several years ago. Works fine. D8050 normally closed.

 

I thank you. Take care, Al

 

FWIW, put some dielectric grease on the single spade. I'm not really all too happy w/ the quality of the D8050 (AC) but it's working. Slide some grease on the spade.

 

If I had to purchase it again, I'd order the STANDARD MOTOR PRODUCTS PS12. I've been happier w/ STANDARD products in the past 5-10 years.

 

I have a tube of that stuff & usually do put some on all connecters I can. What irritates me is the Oil light didn't work when I bought the car. Everything (power & dash bulb) tests OK. I had it replaced while trans was rebuilt. It worked perfectly for a few weeks, then intermitently. Now it's dead. I don't know the brand they used, but can't imagine what goes wrong w/ a simple diaphram/spring switch. I tested it & there's no continuity. Oh well. I already ordered it. Easy to replace.

 

It’s a thermistor - thermal resistor which operates/functions on resistance.

 

An oil pressure switch is a normally closed switch completing the switch to ground that will illuminate the dash warning light. If the engine produces enough oil pressure (typically 7-9 PSI) the contacts will open and the bulb will turn off.
A thermistor changes its resistance with changes in temperature. Typically there are two types. Negative coefficient which starts with high resistance and goes low as temperature increases and positive coefficient which starts with low resistance and goes high with an increase in temperature. In automotive applications these sensors are typically used to measure engine coolant temperature, air intake temperature, and ambient air temperature. In electronically controlled diesel applications they may be used to monitor exhaust gas temperature, EGR system temperature, and selective catalyst exhaust reduction system temperatures. Other applications may include cabin air temperature, HVAC duct temperature, transmission oil and engine oil temperatures.
The signal produced by the thermistor sensor is analog which is converted to a digital signal in the analog to digital signal convertor located in the logic section of the respective control module or when the vehicle is equipped with a CAN BUS a stand alone module will do the conversion. To reduce redundancy the digital signal may be sent over the vehicles CAN BUS system allowing multiple modules to read what ever signal it needs to perform its operating computations. For example both the engine control module may need the ambient air temp signal to calculate fuel mixture and ignition timing. At the same time the HVAC module needs the ambient air temp to process outlet temperature.
There may be other applications and operations but this is enough for now. I pulled all of this from memory so please feel to fact check and edit as needed. I don't like to confuse others with misinformation. Peace my brother and sisters!

 

Buggers. You're correct. When I responded last, regarding the diaphragm/switch - for some odd reason my mind switched to thinking we were talking about a H2O temp. sensor. It happens.

 

I knew what you meant Norm. The cars w/ gages have the resister oil sensors. Mine is the plain idiot light pressure switch. I have an A/C brand switch already ordered for 7.04 from Rock Auto. Next time will get the better one. Thanks again.

Al

 

Norm
No worries, no explanation needed. My reply was to the OP.
And yes it does happen, and no it is not a senior moment. It's because we are doing too many things at the same time. Multitasking.
My New Years wish is we slow down, smell the flowers, enjoy what is in front of us. It's not the destination rather its the trip. Peace every one.​​​​​​​
Richard

 

Richard -

For me it is a senior moment.

 

Sorry Norm, simply being a senior doesn't mean it's a senior moment. Just think for a minute. How many ***** are you juggling right now? You know your stuff just like I do. Look at that five page master piece I wrote. All of that plus 47 years of turning wrenches is constantly churning through my brain like a never ending movie loop. I thank you and everyone on CO for letting me vent it. Let's share our knowledge, enjoy our cars, our hobby, and our comradery. 'Tis the season!