ad8370w5000f

Auxiliary heater, diagnosis, troubleshooting

Type ad · topic 83.70 · version 0100 · 2003-06-16

Applies to: MODEL 625.1 /2, 655, 656, 657, 658, 659 with CODE (H08) Hot water auxiliary heater D 5 W MODEL 650, 651, 652, 653, 654 with CODE (H08) Hot water auxiliary heater D 5 W

Where it sits

Function group 3 Body › 83 Climate control › 83.70 Auxiliary/supplementary heater — Series 625 (models 1**, 2**) · Series 650 · Series 651 · Series 652 · Series 653 · Series 654 · Series 655 · Series 656 · Series 657 · Series 658 · Series 659

AD83.70-W-5000F

Auxiliary heater, diagnosis, troubleshooting

28.1.98

MODEL 625.1 /2, 655, 656, 657, 658, 659 with CODE (H08) Hot water auxiliary heater D 5 W

MODEL 650, 651, 652, 653, 654 with CODE (H08) Hot water auxiliary heater D 5 W

Do not carry out measurements at contact points or plug connections with unsuitable equipment (test probes, wire ends etc.). Always use appropriate test cables from connection set (201 589 00 99 00).

Auxiliary heater (AHE) diagnosis, previous knowledge

AD83.70-W-2000E

Cables, plug connections and fuses are included in the following tests

If heater unit is retrofitted and a third party (e.g. drivers, customers) have made alterations / manipulations or non-specialist repairs have been made, the following test program may only be of limited use. The same applies to wiring diagram.

On-board voltage 22.5-29.5V

(Acid density 1.6 kg/dm3)

Troubleshooting

Complaint

Possible cause

Notes

Remedy

Auxiliary heater does not run with ignition: OFF (after actuation of button with flame symbol on timer).

Fuses

No display of heat duration on timer display:

Check fuse F1-A1, if in order

AD83.70-W-6000-39C

If F1-A1 immediately trips again after being replaced:

- Short-circuit to ground on cab / entry lamp or supply cable.

- Short-circuit to ground on supply cable to timer, possible in timer.

If F1-A1 trips only when button on timer switched on

AD83.70-W-6000-35C

If F2-A5 trips again:

Check D+ input on control unit (B5), its cable or diode on relay K1 on heater unit mount.

If F7-A5 trips again

AD83.70-W-6000-35C

- Display of heat duration takes place when heater switched on, but heater does not start (ignition: OFF)

- Fuse F1 on fuse carrier A1 in order.

Check fuse F6-A5, if in order

AD83.70-W-6000-40C

If F6-A5 trips again:

- Short-circuit to ground on supply cable to control unit, possibly on/in control unit.

- F6-A5 trips again when heater switched on or shortly afterwards

AD83.70-W-6000-28A

Fuse F1-A1 trips when heater switched on or shortly afterwards.

AD83.70-W-6000-35C

Fuse F6-A5 trips when heater switched on or shortly afterwards.

AD83.70-W-6000-28A

- When ignition: ON timer display shows pre-set heat duration for time selection (instead of current time and day).

- Auxiliary heater runs with ignition: ON no longer than programmed time.

- Auxiliary heater runs for longer than 5 minutes after ignition: OFF.

Check fuse F7-A5, if in order

AD83.70-W-6000-44B

If F7-A5 trips again:

- Short-circuit to ground on supply cable to timer, possibly in timer.

- Short-circuit to ground / short-circuit in coil on coolant circulation solenoid valve (Y61) or on its supply cable.

- Short-circuit to ground on supply cable to air circulation flap adjustment, possible on air circulation flap adjustment switch or on/in air circulation flap motor.

- Short-circuit to ground on supply cable to battery master switch on vehicles with battery master switch.

Referenced documents