SEAT Workshop Service and Repair Manuals

Checking auxiliary air heater element -Z35-

Special tools and workshop equipment required

t	Hand-held multimeter -VAG 1526C-

t	Digital multimeter -VAG 1715-

t	Auxiliary cable kit -VAG 1594C-

t	Digital potentiometer -V.A.G 1630-

t	→ Current flow diagrams, Electrical fault finding and Fitting locations

Test condition l  Intake temperature less than 19° C l  Coolant temperature less than 80° C l  Vehicle interior temperature below 20 °C approx l  Battery voltage above 11 V l  Alternator charge not greater than 50% (terminal DF) l  Engine speed above 450 rpm l  Blower speed 4 for fresh air blower -V2- l  Turn the control for the interior temperature as far as it will go in the heating range Checking sequence If the specifications for intake and coolant temperature are not attained, create the following test conditions.

The intake air temperature sender -G42- and thecharge air pressure sender -G31- are mounted on a housing located in an intake pipe. –  Connect the digital potentiometer -V.A.G 1630- to the connector of the coolant temperature sender -G42- between pins -1- and -2-.

Specification: see diagram. The area -A- indicates the resistance values for the range of temperatures from 0 ... 50 °C and the area -B-, the range of temperatures from 50...100 °C. Example: t  10 ℃ corresponds to a resistance value of 3,500 ... 4,000 Ω t  80 ℃ corresponds to a resistance value of 275 ... 375 Ω

–  Pull connector off coolant temperature sender -G62- → Rep. gr.23. –  Connect the digital potentiometer -V.A.G 1630- to the connector of the coolant temperature sender -G62- between pins -1- and -2-.

Specification: see diagram. The area -A- indicates the resistance values for the range of temperatures from 0 ... 50 °C and the area -B-, the range of temperatures from 50...100 °C. Example: t  40 ℃ corresponds to a resistance value of 1,000 ... 1,500 Ω t  80 ℃ corresponds to a resistance value of 275 ... 375 Ω

–	Connect multimeter -V.A.G 1715- to supply wire for auxiliary air heater element -Z35- using pick-up clamp.

–	Set multimeter -V.A.G 1715- to amp test.

Ten seconds after the engine has been started, the auxiliary air heater element -J248- is enabled for heating by the diesel direct injection system control unit -Z35-. The three heating elements are switched on and off by the engine control unit in stages via relays.

–	Start engine and leave running at idling speed.

In vehicles with air conditioning, it will have to be disconnected.

The starting current for auxiliary air heater element -Z35- is approx. 38.9 A and more at the set test conditions. After an operating period of approx. 10 minutes of the auxiliary air heater elements -Z35-, the power consumption reduces to approx. 31.6 A. If this falls to approx. 10 A or more, the lines must be checked using the circuit diagram → Current flow diagrams, Electrical fault finding and Fitting locations.

If no fault in lines is detected:

–	Replace the heating element of the additional heating -Z35- → Chapter

–	Clear fault memory → Rep. gr.23.

Note In vehicles with air conditioning, it will have to be disconnected.