david1289

Having continued issues with my fan switch. Using Napa FS113 switch in 92' t-stat housing, with single lead going to relay ground. Fan switch will work for short period of time and quit. I can ground the relay and fan will kick on. I tested the relay ground, and there is some voltage, when ground is applied. I have tried several relays, and all seem to produce same result. Fan works with AC and de-froster. Any help is greatly appreciated.

Lowrange2

When you're applying ground to the relay are you grounding the sensor wire or are you applying the ground to the relay socket?

What I'm getting at... do you have a good connection between the sensor and relay.

Have you tested resistance of the sensor when hot and cold to verify that it's working?

david1289

I have tried gounding with my lead to relay, and directly to the relay socket, both will activate the OEM fan relay and fan itself. In addition I have grounded both directly from the battery as well. I am using a Napa switch and have found some posts where the switchs do go bad. The switch was working as the fan was kicking on and off for a couple of hours last weekend, then I noticed temp. rising again. Just not sure about the voltage off the relay ground when the relay is activated.

Thanks for the reply.