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

Thermo-Vacuum Switch




1. With the engine coolant temp below 10°C (50°F), or with the thermo-vacuum switch removed from the car and cooled, connect a vacuum pump to the angled connector of the thermo-vacuum switch.
2. Momentarily seal off the straight hose connection and apply vacuum to the angled connection.
3. Open the straight connection, and the vacuum should release (switch should be open when cold).
4. If the switch is not open, replace it.