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Potentially serious wiring fault
This is NOT a joke - Please do NOT disregard this message...
Whilst investigating the root cause of my inoperative headlamp washer system, I dug out the relevant schematics to give me the relay pinouts.
I removed the relay for the headlamp washers (J39) from position 4 in the main fusebox and used a jumper wire to try to temporarily feed the headlamp washer pump with 12V... This eliminating J39 from the system as I thought it the most likely culprit. The pump didn't make any noise so its either totally dead or I have a wiring fault between the fusebox and the headlamp washer pump.
What *REALLY* worried me, when I studied the schematic, is that the unswitched 12V feed (T30) to the headlamp washer pump (thru the relay) is shown as being UNFUSED. This is potentially horrific as if the pump fails in a short circuit condition there is going to be meltdown of the wiring loom as there is nothing to stop excessive current draw from the battery.
Likewise if the relay fails internally with a short condition from 12V (T30) to earth (T31) then its a serious fire risk... At best you are looking at major damage to the wiring loom.
Its horrendous. More investigation is required, but consider yourselves warned. My headlamp washer pump (or the wiring to it) has failed in an open-circuit condition thank goodness.
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As a short term safety measure I recommend that everybody removes Relay 4 from their main fusebox. This is currently (no pun intended) the only way to break the potentially hazardous circuit without modifications to the wiring loom.
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For those with schematics - Refer to the 1994 Coupe/Cabriolet binder (000.5201.57.20) - Sheet 1/16 - Track 167. I have the latest edition (20) dated 11/99 AFAIK. The date on sheet 1/16 goes back to 08/93.
For those without schematics I'll scan the scarey page. For those without any electrical experience I shall annotate another version of the schematic with the relevant information.
Regards,
Paul
Whilst investigating the root cause of my inoperative headlamp washer system, I dug out the relevant schematics to give me the relay pinouts.
I removed the relay for the headlamp washers (J39) from position 4 in the main fusebox and used a jumper wire to try to temporarily feed the headlamp washer pump with 12V... This eliminating J39 from the system as I thought it the most likely culprit. The pump didn't make any noise so its either totally dead or I have a wiring fault between the fusebox and the headlamp washer pump.
What *REALLY* worried me, when I studied the schematic, is that the unswitched 12V feed (T30) to the headlamp washer pump (thru the relay) is shown as being UNFUSED. This is potentially horrific as if the pump fails in a short circuit condition there is going to be meltdown of the wiring loom as there is nothing to stop excessive current draw from the battery.
Likewise if the relay fails internally with a short condition from 12V (T30) to earth (T31) then its a serious fire risk... At best you are looking at major damage to the wiring loom.
Its horrendous. More investigation is required, but consider yourselves warned. My headlamp washer pump (or the wiring to it) has failed in an open-circuit condition thank goodness.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
As a short term safety measure I recommend that everybody removes Relay 4 from their main fusebox. This is currently (no pun intended) the only way to break the potentially hazardous circuit without modifications to the wiring loom.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For those with schematics - Refer to the 1994 Coupe/Cabriolet binder (000.5201.57.20) - Sheet 1/16 - Track 167. I have the latest edition (20) dated 11/99 AFAIK. The date on sheet 1/16 goes back to 08/93.
For those without schematics I'll scan the scarey page. For those without any electrical experience I shall annotate another version of the schematic with the relevant information.
Regards,
Paul
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