No warm air flow

Step 1: Warm air duct

Check warm air duct from heater to body for tightness

Possible defect	Remedy
Clamps loose or hoses dropped down or damaged	Secure loose parts, replace damaged parts with new ones

Step 2: Fuel delivery

Loosen hose clamp, disconnect hose to heater briefly (2 secs) at fuel pump, then check whether fuel is delivered by pump. Catch escaping fuel in a cloth.

Possible defect	Remedy
Check fuel supply	Fill fuel tank
Fuel filter blocked	Install new fuel filter
Strainer dirty	Clean strainer
Fuel check valve blocked	Replace fuel check valve and readjust delivery capacity

Step 3: Glow-spark plug

Switch heater off. Remove glow-spark plug and check

Possible defect	Remedy
Thermo switch defective (no current, glow time too short)	Install new thermo switch
Glow element open	Install new glow-spark plug
Glow-spark plug dirty	Clean glow-spark plug
Ignition contact breaker defective or maladjusted	Adjust contact breaker or replace if necessary
Ignition cable or coil defective	Test ignition system and install new parts if necessary