MG TF 2004-2005 Driver Window Opens or Horn Sounds all by Itself?

MG TF (VIN RD 620459 to 639732)

Symptoms:

SCU MALFUNCTION – TRANSIENT SPIKE FROM WIPER MOTOR

During windscreen wiper intermittent wipe operation, involuntary operation of either of the following may
occur:

• The drivers window may open
• The horn may sound
• Auxiliary lamps may flash on and off

Cause:

This condition is caused by the emission of a high voltage transient spike from the wiper motor system during intermittent wipe operation. This causes the SCU to malfunction may result in the above functional problems.

Suggested solution:

Technozen (Paul Brown):
Code:
Due to the variations in electrical interference generated by the wiper motor MG-R fix does not always work. The suppressor is most effective when fitted as close to the motor as possible. A solution that works 100% is to use a 0.22uF Class X2 capacitor, such as Maplin N70CN and connect it accross the Green/Silver and Brown/Green wires at the front wiper motor. Make sure to insulate all connections, heatshrink sleeving is the best way of doing this.

NOTE: Taken from here https://www.mg-rover.org/threads/phantom-electrics.485771/page-2#post-5184476



Solutions from other website:

https://mgtf-de.translate.goog/tech/wischer/index.html?_x_tr_sch=http&_x_tr_sl=auto&_x_tr_tl=en&_x_tr_hl=en



Original MG-Rover Technical Tip solution mentioned above:


1. Remove lower facia closing panel from drivers side.
2. Remove the upper half of the steering column cowl.
3. Locate the rear of the wiper switch and disconnect the 8 way connector.
4. Referring to illustration 1, locate and remove the 10mm fixing nut ‘A’ from the in-car fuse-box as shown.



5. Obtain suppressor ‘B’ (part number XBS000040) and position the earth foot between fuse-box lug and the fixing bracket with the suppressor facing up. Refit fuse-box fixing nut and tighten.
6. Route the suppressor fly-lead up the steering column so that it terminates adjacent to the wiper switch connector and cut off the bared wires from the end of the lead.
7. Using the IDC connector (part number YPC116330), connect the suppressor fly-lead to the ‘Blue and Light Green’ wire at the rear of the wiper switch connector (illustration 3).



8. Using black electrical tape, secure the fly-lead to the steering column harness protection, ensure that flylead is tidy, i.e. that no hanging wire sections exist.
9. Refit the wiper switch connector.
10. Refit the steering column cowls and closing panel.

NOTE Originally suggested suppressor XBS000040 is 3.3uF.

Original MG-Rover Technical Tip TT0121:

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Last Edit:9 months 5 days ago by Roverlike
Last edit: 9 months 5 days ago by Roverlike.
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