I experienced overheating in my 235 equipped '58 so I decided to start small and work bigger. I replaced the thermostat, had the radiator pressure/flow tested, replaced the sending unit, and bought a new temp gage. While purchasing the temp gage from Chevy Duty, I went ahead and bought a "cluster decal kit" ($6) so that the Amp/Oil/Gas gages wouldn't look like 48 year old gages when compared to the brand new temp gage. I ran into some trouble and once again need to rely on my Stovebolt contacts for help:
The old gage, which was the original I believe, had a single post on the back. Granted, it was broken, and if there was another terminal, it was no longer part of the assembly. The new gage has two posts. I looked at the wiring schematic that is in the shop manual and I'm completely unimpressed. It doesn't show me any real information that I can use, such as wire color. I made a huge mistake and connected a stray red wire to the left (outboard) terminal of the gage, and the previously-connected green wire (from the sending unit) to the other terminal of the gage. As soon as I powered up by turning the key to ign, I got all kinds of smoke, stink, etc. I'm certain I cooked that dang brand new gage as soon as I turned the key. (There are resistors in the new mechanism and I doubt these could withstand such stupidity.)
After messing with it for a while, I finally pulled my head out of my derriere, and disconnected the red wire altogether. Lo and behold, the other gages began working correctly and the arcs stopped.
My question is: given two termimals on the back of the brand new temperature gage, what is connected? I tend to think I should only connect a green to the terminal on my right hand side (closest to the steering column.)
What is the other terminal for?
When I connected the stray red wire to the gage, the Ammeter and Gas gages stopped working and the red wire's insulation melted.
Please help with any experience you may have to offer. My engine is dependent upon me knowing the temperature, and I know that I must order another unit, but I'm reluctant to install it until I know what I did wrong.
A word of caution to those of you considering ordering a temp gage from Chevy Duty: I ordered a gage for a 1958 and coincidentally ordered a cluster decal set to update the look of my Amp/Oil/Gas gages. The gage provided, even though it is labeled '55 - '59 in the catalog, is for a 1955. It has only three dots (low/med/high.) I had to install a '56 - '59 decal over a brand new gage to make it look correct for 1958 (low dot, normal temp line, high dot.) I'm a little miffed at Chevy Duty for using the '55 for all years '55 through '59 without letting me know. I had a fix THIS time, but when I get my new gage to replace the one I fried, I'm going to have to move the decal. If I didn't buy the decal, I'd have an incorrect '55 readout.
Bill
