$1900 is more than it is worth. The temperature should run slightly under half so 3/4 indicates to me that a problem has occured. The trunk wire thing is real common on the early LS400's and since there are several wires, I have heard of (and experienced) all kinds of problems with that situation. Took me a long time to unwind all the old, black sticky tape but there it was, bigger than Dallas, two broken wires and one about to break. I added extra length and then left it kind of loose since my first repair tore after I forced it back into the channel. Hey, put your location on, it really helps with helping you.
Denny