Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Coolant Switch Test

1. With ignition switch in "Off" position, disconnect wire from coolant switch.
2. Check continuity between coolant switch terminal and the engine ground. The ohmmeter readings should be as follows: Engine cold, below l50°--Continuity should exist. If not, replace coolant switch. Engine hot, above 150°--No continuity should exist. If continuity exists, replace coolant switch.