COLD light not working

[Timsnewporttwin]

Hello everyone,

Laugh if you want, but the COLD light in my 65 Newport is one of my favorite things about the car. It was working fine but then became intermittent and now its just not working at all. Sending unit has been replaced, bulb/socket is good and I even cleaned the contacts where the bulb socket goes into the cluster. Also checked plug at temp sending unit. but it is the original harness. Im thinking maybe the circuit board may be the problem ? The Hot light works without problems (and far more important) but I've got have my cold light . Silly, I know....but any ideas ?

Thanks !
Tim

 

[CBODY67]

When the same thing happened on our '66 Newport Town Sedan, it was noticed, but seemed to cause no issues, so we might have had the sendinging unit replaced, but I don't recall. If we did, a few years later, same thing, no "COLD" light when the engine was first started.

BUT as long as its companion "HOT" light stays out, I'm not worried. If it's cold enough to use the heater and the heater works, that's all that matters. Key thing is that the "HOT" light stays out!

I concur that it is a neat feature, but I can tell enough about how things are doing without it.

Your car, your time/money, your desires.

Enjoy!
CBODY67

 

[Davea Lux]

Test the sending unit. Take a voltmeter set to resistance, one terminal on the sending unit will be open with the engine cold, the other should show a completed circuit with low resistance (cold light circuit). The sending unit causes the ground to be active. Test the harness by using an alligator clip to ground across one terminal on the plug, either the "Hot" or "Cold" should light up. If the cold light does not come on, either the bulb is bad or the circuit is open somewhere.

Dave

 

[Big_John]

There's 4 components to this... Power, the bulb, the sender and the wiring.

First check is the power. Real easy.... When you twist the key to start the car, the "Hot" light should illuminate. If it does, you have power. The cold light circuit shares the power with the hot light.

Next, check the sender. With the engine cold, unplug the wires at the sensor. You'll need a multimeter (cheap one will work fine) or some sort of continuity tester. Check both contacts for continuity to ground. One contact should have continuity to ground. If the wiring is like slightly later cars, that contact should be the one the gray wire connects to.

Next to check the wiring and bulb. With the wires still disconnected, make up a jumper from the gray wire (on the harness) to a good ground. Start the car and the bulb should work. If it doesn't the problem is either the bulb or the circuit to the bulb.

 

[bigmoparjeff]

Hi Tim,

I too have always thought that the cold light was a really neat feature. The '69 and up cars are a bummer in that the lens is no longer green. It's black with "COLD" in a washed out, barely green lettering.

The number one suspect for your problem would be the pins on the back of the cluster that mate with the big round connector. It's quite common for them to snap off of the printed circuit board. A less likely trouble spot would be the bulkhead connector.

I see that you are in Lee, Mass. I spent the first eight years of my life in Lenox. I still have a fairly vivid memory of hanging around at the laundromat in Lee during the time that our washing machine was broken. Looking at Google Earth, I think it was the little building on the corner of US 20 and Canal St. A lot of things have changed since then. I think the bridge on 20 was a steel structure at the time. I believe we would go to Lee for Kentucky Fried Chicken and Dairy Queen, both of which are gone now.

Jeff

 

[Timsnewporttwin]

Hi Tim,

I too have always thought that the cold light was a really neat feature. The '69 and up cars are a bummer in that the lens is no longer green. It's black with "COLD" in a washed out, barely green lettering.

The number one suspect for your problem would be the pins on the back of the cluster that mate with the big round connector. It's quite common for them to snap off of the printed circuit board. A less likely trouble spot would be the bulkhead connector.

I see that you are in Lee, Mass. I spent the first eight years of my life in Lenox. I still have a fairly vivid memory of hanging around at the laundromat in Lee during the time that our washing machine was broken. Looking at Google Earth, I think it was the little building on the corner of US 20 and Canal St. A lot of things have changed since then. I think the bridge on 20 was a steel structure at the time. I believe we would go to Lee for Kentucky Fried Chicken and Dairy Queen, both of which are gone now.

Jeff

Thanks Jeff, I've been thinking the cluster may be the trouble. I had the entire dash out of this car, it was in really rough shape. I have a NOS circuit board, but it's a nightmare to get cluster out. But I'll do it. Yes I'm in Lee. The Kentucky Fried bldg is still here but it's a heating/ac place now. You can tell it was a KFC though. Dairy Queen long gone.
Thanks for help

 

[Timsnewporttwin]

Thanks for all the info everyone ! I knew I'd get an answer, glad I joined the club. My car was left for dead under trees for 25 plus years, survived it all and motor hunters too. It's come a long way and deserves this fix !

 

[bigmoparjeff]

Compared to some of the other Chryslers, it's not too bad to get the cluster out if I'm remembering correctly. My '66 had a tilt column, so I don't know if that would have made things a bit easier. While I had mine out, I also wired up the green turn indicators in the cluster so that they would function. At least in '66, Chrysler didn't connect them if the car had fender mounted indicators.

Jeff

 

[ravenscat]

My stopped cold light stopped working too. I miss it! Might the fix for mine be suggested by the fact that once or twice I got it to light up by tapping on it right where it lights up on the dash?

 

[Big_John]

My stopped cold light stopped working too. I miss it! Might the fix for mine be suggested by the fact that once or twice I got it to light up by tapping on it right where it lights up on the dash?

That's probably a bad bulb. By tapping it, you can sometimes get the filament in the bulb to move and make contact again. That's a very temporary fix... possibly minutes.

Note word "probably" and go up to post #4 for how you can check this.

 

[Gerald Morris]

I LOVE the 1965-66 instrument cluster! Here's a restorative fix for oxidized circuits on your board: copper foil! you can stick it over old circuit traces, or/and use a little flux, solder it down in key areas of the old board, tin it over, et Lux facta ergo est! I used this on my '68 instrument panel for the turn signal indicators. The old stuff had oxidized to green powder....

 

[ravenscat]

Thanks much for the cold light dash info. I’m walking on eggshells on this forum because I’m not tech savvy and very afraid that I am not asking the question properly and in the correct format.

 

[Big_John]

I’m walking on eggshells on this forum because I’m not tech savvy and very afraid that I am not asking the question properly and in the correct format.

Here's my 2 cents, or 8 bucks with inflation....

I have said this many times in my life... We were all born knowing nothing and have to learn everything. I usually make some comment about my brother knowing everything, but I digress.

Another thing I've said is there is no dumb question, just dumb answers.

The thing to do when asking questions is to present everything you know has happened and EVERYTHING you did to try to cure it. Also say what you are working on, year, make and model. Those are the two things that drive me a little crazy (it's a short drive) and make it so much harder to help.

With that, another thing is if you have solved the problem, tell us what you did to fix it. Let's all learn from your experience too.

Then just ask... If you aren't "technical", that's fine... Say that so we can try to explain to the level you are at... In other words, I might give a short, quick answer to someone that I know works on old cars and a more detailed and possibly simplified answer.

We're all here for the enjoyment of our cars and a bit of comradery with guys that share our interests.

 

[Gerald Morris]

Thanks much for the cold light dash info. I’m walking on eggshells on this forum because I’m not tech savvy and very afraid that I am not asking the question properly and in the correct format.

STOMP THE EGGSHELLS BRO!!! Granted, I possess a modicum of technological prowess, folks say, yet I never learned a quark's mass of that by tentative inquiry. To wit: if you NEED TO KNOW, ASK!

These old Mopars have SUPERB documentation! Some of this comes from the once friendly relationship Chrysler Corp cultivated with its CUSTOMERS, UNLIKE THESE FOREIGN VAMPIRES OF STELLANTIS NOW!

View, and learn:

Uncle Tony teaches well. Get a FSM from mymopar.com. If you MUST, spend a little $$ for one. Admittedly, the 1965-66 FSMs are FAR superior to those of a mere decade later, so rejoice in having such a car! I would dearly LOVE to put another on the road w my name on the title.

Welcome to driving a REAL CAR!