I brought my truck into local shop to get steering box changed, mechanic phoned me and said he took it for a ride around block after and than parked it. After a couple minutes he noticed smoke coming from under hood and opened hood and intake manifold was smoking, He called me and I rushed there and told him the grid hearer was stuck on. by that time the batteries were dead. I could not find a relay in box for the grid heater. Is there one? We unhooked cables to grid heater and have the batteries on charger now. The only cable he removed was the left battery ground cable off engine. He put back on before test ride. What would cause the heater to stay on?

 

Picked up truck and drove to store, shut off , went home shut off and everything is back to normal now. I removed grid heaters tonight to examine them for burnt elements, everything was good. Strange that they stuck on.

 

Not really. Considering the relays are almost 20 years old and like me they see a lot of use, they will wear out. I have already replaced mine on both riggs.