The temperature gauge on my 89 SR5 3VZE 4Runner works, but often reads regular operating temp when I first start the truck. I pulled the gauge assembly today thinking it was a broken wire like found in the Definitive Temp gauge fix in the sticky of this forum. No such luck. I didn't have any wires broken, or at least nothing I could see. Per the FSM, I measured resistances across the back of the gauge. My numbers were not within factory spec.

They should be:
IG - TU 135 ohms
TU - E 138 ohms
IG - E 273 ohms

Mine read:
IG - TU 75 ohms
TU - E 160 ohms
IG - E 85 ohms

So my gauge appears faulty. FSM says to replace. I just checked and found the SR5 temp gauge is P/N 8324489336 and is $155 + Shipping. Ouch. Are there any other options? I really don't want an aftermarket gauge.

 

You can try refreshing the solder joints on the flexible circuit board for a start.