65 cold light

[jframe]

Pretty sure it may be a bad sender, but the cold light quit coming on. Ground one side of the plug and the hot comes on but the other side grounded wont turn on the cold. However the engine had been at operating temp when I tested it. If it IS the cold bulb, what's the easiest way to get to it for replacement? Sure don't care about pulling the cluster at ALL.

[Jim Cannon]

You do NOT need to pull any cluster to get to the Cold light. If you are a contortionist and have small hands, you can get to it from underneath by removing the little access panel on the underside of the dash, down low. Work up from there.

 

I prefer to remove the dash pad and access the bulbs from above.

 

The Cold light should come on when you have a dead cold engine (after sitting overnight) with the key on and engine not running. Or, as you did, by grounding the wire that plugs on to the sender (but the key must be in the Run position). If no Cold light, the bulb is probably blown.

 

The Hot light comes on momentarily to test the bulb when you turn the key to the Start position. As soon as you release from Start, the Hot light should go out.

 

HTH.

[telriv]

Mark,

 

Remove the cluster lens with the one Allen head screw & I'm pretty sure the cold light bulb can be replaced WITHOUT being a contortionist & going under the dash. Worth a try for 5 seconds of time.  

 

Tom T.

[Pat Curran]

20 hours ago, telriv said:

Mark,

 

Remove the cluster lens with the one Allen head screw & I'm pretty sure the cold light bulb can be replaced WITHOUT being a contortionist & going under the dash. Worth a try for 5 seconds of time.  

 

Tom T.

I have done this in the past and I think it is the easiest way to change the bulbs.

[jframe]

1 hour ago, Pat Curran said:

I have done this in the past and I think it is the easiest way to change the bulbs.

I pulled it off Saturday, and the cold light is buried back in the plastic, where the actual dash bulbs are up to where they can be accessed from the front.

[telriv]

Good to know my memory is still being correct.

 

Tom T.

[jframe]

Accessed the bulb under the dash, and replaced it. No dice. When I turn the switch on a cold engine, neither the hot or cold light comes on. When I unplug the switch and ground the dark green wire, the hot light will come on with the ignition turned on. When I ground out the light green wire for the cold light, I still get nothing when the ignition is turned on. Thinking towards a sending unit now, but the original seems to be welded into the head, lol. Sprayed the threads with some Liquid Wrench last night, hoping for it to loosen.

[Riviera63]

1 hour ago, jframe said:

Accessed the bulb under the dash, and replaced it. No dice. When I turn the switch on a cold engine, neither the hot or cold light comes on. When I unplug the switch and ground the dark green wire, the hot light will come on with the ignition turned on. When I ground out the light green wire for the cold light, I still get nothing when the ignition is turned on. Thinking towards a sending unit now, but the original seems to be welded into the head, lol. Sprayed the threads with some Liquid Wrench last night, hoping for it to loosen.

If you go with a new sending unit test it  before installing. This could save you some time. I took mine in because the cold light wasn't lighting. I did not even know it had a cold light until someone mentioned it on the forum. I took it  to my mechanic because I was pretty sure it was the original and thought they were better equipped than me for a frozen unit. They were getting units from NAPA and went through 5 before they got a fully functional unit.

 

Bill

[Jim Cannon]

12 hours ago, jframe said:

Accessed the bulb under the dash, and replaced it. No dice. When I turn the switch on a cold engine, neither the hot or cold light comes on. When I unplug the switch and ground the dark green wire, the hot light will come on with the ignition turned on. When I ground out the light green wire for the cold light, I still get nothing when the ignition is turned on. Thinking towards a sending unit now, but the original seems to be welded into the head, lol. Sprayed the threads with some Liquid Wrench last night, hoping for it to loosen.

Mark-

If you cannot get the COLD light to come on when you ground the light green wire with the ignition on, then the sender is NOT the problem.  The wire between the sender and the light on the instrument panel has an open connection somewhere, that's your problem.

 

Or a bad bulb.

 

Or a bad bulb holder.

 

 

 

Edited May 4, 2022 by Jim Cannon (see edit history)

[jframe]

On 5/3/2022 at 8:34 PM, Jim Cannon said:

Mark-

If you cannot get the COLD light to come on when you ground the light green wire with the ignition on, then the sender is NOT the problem.  The wire between the sender and the light on the instrument panel has an open connection somewhere, that's your problem.

 

Or a bad bulb.

 

Or a bad bulb holder.

 

 

 

Tending to agree with you now for sure, Jim. I can ground the hot light and the hot bulb will come on without the switch being turned. Plug it back up, and the hot light won't come on at all. Can't get ANYTHING out of the cold light, no matter what I do, and I have replaced the hot and cold bulbs. Think I'm just going to get a good quality (if there is such a thing) mechanical temperature gauge and try to mount it somewhere that's not too obtrusive. The ashtray is out because I have my USB port there.

[71GS]

On 5/6/2022 at 8:32 AM, jframe said:

Think I'm just going to get a good quality (if there is such a thing) mechanical temperature gauge and try to mount it somewhere that's not too obtrusive

Mark, I installed new gauges over the winter as I wanted to add an oil pressure gauge. These are Stewart Warner green lines. 

 

That said, I removed a Stewart Warner mechanical temp gauge that worked perfectly and has a polished stainless mount bracket. You can see it It the other picture, It’s yours for the shipping if interested. 

Brian

 

Edited May 10, 2022 by 71GS (see edit history)