Outdoor temperature

My 90 convertible outside temperature always reads -40. Is this a sensor that needs replacing and are they still available

Considering your location, it may be reading correctly.

John F.

Guess you really have had a brutal winter.

You can check the sensor with an ohm meter and the circuit with a volt meter.

Unplug connector to sensor and measure resistance across it using at least the 20K ohm scale. The -40 reading your seeing is the end of range which tells me your sensor is an open circuit or possibly a dead short. I'm guessing it is the open circuit (think a short will report a 255 reading). You should get a reading. If the meter reports no reading, raise the scale to the max and check again. If you still don't get a reading, the sensor is open and needs to be replaced. Likewise if you get a 0 reading or close to it, lower the scale to the lowest and read again. If you get a close to 0 reading, touch the two probes together and then check reading. If it's the same as across the sensor, the sensor is shorted and needs to be replaced.

If you do get a resistance across the sensor (I'm guessing somewhat it will be about 20 on the 20K ohm scale) then the sensor may be OK, but the circuit from the BCM and to ground may be at fault. Set meter to 20 volt DC scale and read from the green wire in the connector to a good ground point with the ignition turned to run. You should get a 5 volt reading. If not, the BCM or the wire from it will be bad. If you get 5 volts, then check the other black/pink wire provides a good ground. Set meter back to lowest ohm setting and read from the black wire to a good ground point. Should read very close to 0 ohms. If not, check the wire, connectors, and splice for any problems.

Other option is just to wait for the spring thaw.

RockAuto shows a listing for the ambient air temperature sensor and you can also grab a used one from a yard or one of our vendors. Was probably used on many high end GM cars of that era. Not a high failure part.

The -40 temperature that is reading on my Reatta has nothing to do with the outside temperature here. It was reading that when the car came out of Florida when i purchased it. Although it does get cold here in the winter, and we did have a bad winter this year, it is not -40. I have been in many places in the USA that is just as cold as here. I do not drive any of my collector cars in the winter, but now that spring is here i have got them out .The temperature here today was around 70. I dont know why some Americans think it is so cold here all the time. I thought this forum was meant to help out other Reatta owners not make fun of our weather. I have ordered a service manual so hopefully i can repair any problems i encounter and not have to ask forum members for assistance.

uhhh, if you provided the info provided in your last post (-40 since Florida, etc.) you may have not received the jokes!

go with McReatta's advice on checking the sensor. we really are here to help!

Instead of looking at/commenting on the positive, knowledgeable and lengthy discourse posted by a forum member who unselfishly spent his own time writing to help you out, you chose to take umbrage to some silly comment I made in the wee hours of the morning before I left for work.

Being new to the forum, maybe you could hold off on the judgements until you spent a bit more time here and got to know us a bit better.

Prior to living in the God-forsaken land known as Northwest Indiana, I lived in White Bear Lake, Minnesota where, in the summer, we had temps as high as 102* in July and as low as -20* with windchills near -50* in the dead of winter and sometimes even in the spring. That's where I got the idea that it gets really cold outside, in the northern latitudes, in the winter. Not "all the time".

Sheesh. Lighten up!

John F.

Edited April 22, 2014 by Machiner 55 (see edit history)

I have been in Winnipeg in the winter to do some consulting work, and it may not have been 40 below but damn close. Lighten up a bit a.

We do go out of our way to help each other, especially new members.

I have ordered a service manual so hopefully i can repair any problems i encounter and not have to ask forum members for assistance.

Welcome to the forum. I wouldn't count on the service manual to negate the need to seek advice when you have a problem. Service manuals have a lot of information that can guide you when you are repairing your Reatta. The problem with them is they cannot answer all your questions when when you encounter something you don't understand. This forum usually can.

A manual can't replace hands on experience. I think the information on this forum is so helpful that I have condensed many of the posts down to tutorials and posted them on my website... knowing quite well that the service manual is readily available on another website for free.

Wait until he installs a thermostat using the manual as a guide then pulls his hair out wondering why it's not working properly.

John F.

Boy, am i sorry i asked about the problem with my Reatta. I am also sorry i replied the way i did. It seems that sometimes it is to easy to press the submit button on your computer before you have had time to think through what you have said. I would like to thank MCReatta for his advice and i have not had a chance to check it out yet. Contrary to what i take from some of the replies, i am not new to dealing with problems with cars, and some of the cars i have owned were a lot rarer and harder to find parts and information on than the Reatta. I have been interested in Reattas since my sister purchased a new one in 1988 and this is the second one i have had. I have been involved in the antique car hobby for many years, am a past President of St Lawrence Valley AACA and look forward to enjoying my Reatta along with my other cars. (By the way Winnipeg is over 1300 miles from where i live)