Generac — Testing High Temperature Shutdown
Testing & diagnosis · High coolant temperature switch
From a Generac service manual covering: IM100G, IM80G, NP100G, NP80G. Check it applies to your exact model before use.
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Procedure
- Disconnect Wire No. 85 from the switch terminal.
- Start the engine, let it stabilize and warm up at no-load.
- Hold the terminal end of Wire No. 85 into contact with a clean frame ground on the engine.
- After a short delay, the engine should shut down.
Tools required
- Ohmmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Switch contacts close at about 225-235° F. (107°-113° C.)
Source: Generac service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.