Another test you could do along with testing the otterstat is to unplug the wires from it and place a jumper wire between them. This should keep the fans running continuously (with the ignition key in the run position). If you notice that it's still "chattering" then I would look else where in the circuit, start from the beginning. You may have a break in a wire or a loose connection. Steve --- In dmcnews@xxxx, "Walter" <Whalt@xxxx> wrote: > David, > > You say that your fan fail light flickers and the fan relay clicks > frantically sometimes when the fans come on. It shouldn't do this. I am > suspicious that you have a bad otterstat. This gadget is a switch that is > activated by a bi-metal strip. Two different metal alloys are layered > together. One alloy is more temperature sensitive that the other, so when > the temperature changes, it tends curl or warp. This triggers the switch. > It sounds like your problem may be that something inside this switch is > loose. When working properly, it is supposed to switch off when at several > degrees cooler than when it switched on. This is supposed to reduce the > chance of rapid cycling. In your case, it sounds like this mechanism has > gone to the other extreme where the coolant has to be luke warm before the > otterstat will switch off. When the switch comes on, it may be holding the > contacts closed with only mediocre force which would explain your flickering > light and chattering relay. > > I have done this test before: take the otterstat out and put it in a > shallow pan of water with a thermometer. Heat it on a stove with a > continuity meter allegator clipped to the otterstat. You will be able to > see at what temperature it switches on and off. While you are at it, check > your original otterstat the same way and compare. Since you seem to be > having such bad luck with otterstats, I suggest checking any new ones the > same way before you put them on the car. > > Let us know what you find. > > Walt Tampa, FL