Well, I just installed new low and high speed fan relays and disconnected delay relay. Checked relay operation and the low speed relay clicked the fan on at 165 degrees (couldn't get it to 190 to test high speed relay). To no avail. Problem persisted. So I tried cutting off just the 12V source to the gauge and reconnecting after starting the engine. No help! Gauge continues to initialize properly if I just turn key on but goes to sender error as soon as I start the car. Remaining possibilities include alternator (I have a new original style alternator on the shelf which I will install when it turns a little warmer) and the starter (been thinking of installing a mini starter for awhile). Other than those two I am at wits end.