rachaeljf
True Classic
The VW 99 relay is effectively a changeover relay with some electronics on top, more about this below. There appears to be two types, one with variable interval and the other with fixed interval. The variable type has an arrow on the electronics on the wiring diagram printed on its side (with thanks to the Sterling Kit Car forum):
Here is another circuit diagram:
Regarding the above diagram: Interestingly, this diagram shows a connection between the motor low speed and the switch and the 53M wire tees in. Studying the Fiat diagram, it does seem that this should be ok as when the stalk is in the intermittent position, all the various grey wires are floating and only the intermittent relay can add any juice. I was worried there would be some unwanted interconnection that would override the intermittent relay, but it seems ok and that was a red herring.
I'm not sure the direct connection of the ground to the park switch is correct, as it appears that every time the motor passes the park position the motor supply is momentarily shorted to ground, given that 53M and 53S are internally connected when the 99 relay is inactive. Fiat takes care of that by having the ground wire (blue/white) floating whenever the motor is running and only grounded when the stalk is in the off position. Also I would never have the 12V supply to the park switch permanent as that's a trapped finger or poked eye waiting to happen.
Regarding the 99 relay and its operation: If no power is applied to any pins, pins 53S (=87a) and 53M (=30) are internally connected same as a changeover relay. When the relay's brain commands a sweep, it fires the relay coil to disconnect 53S from 53M and instead connect 15 (=87) to 53M. Applying 12V to terminal T (=86) also activates the relay and its brain keeps it activated for three wipes after you remove the 12V.
Can you confirm that with the 99 relay in your hand, pins 53M and 53S are connected? Also, did operating the washer give you three sweeps of the wipers?
Here is another circuit diagram:
Regarding the above diagram: Interestingly, this diagram shows a connection between the motor low speed and the switch and the 53M wire tees in. Studying the Fiat diagram, it does seem that this should be ok as when the stalk is in the intermittent position, all the various grey wires are floating and only the intermittent relay can add any juice. I was worried there would be some unwanted interconnection that would override the intermittent relay, but it seems ok and that was a red herring.
I'm not sure the direct connection of the ground to the park switch is correct, as it appears that every time the motor passes the park position the motor supply is momentarily shorted to ground, given that 53M and 53S are internally connected when the 99 relay is inactive. Fiat takes care of that by having the ground wire (blue/white) floating whenever the motor is running and only grounded when the stalk is in the off position. Also I would never have the 12V supply to the park switch permanent as that's a trapped finger or poked eye waiting to happen.
Regarding the 99 relay and its operation: If no power is applied to any pins, pins 53S (=87a) and 53M (=30) are internally connected same as a changeover relay. When the relay's brain commands a sweep, it fires the relay coil to disconnect 53S from 53M and instead connect 15 (=87) to 53M. Applying 12V to terminal T (=86) also activates the relay and its brain keeps it activated for three wipes after you remove the 12V.
Can you confirm that with the 99 relay in your hand, pins 53M and 53S are connected? Also, did operating the washer give you three sweeps of the wipers?