Intermittent Wipers (Again)

[julianhensman]

I am trying to install an intermittent wipe function in my TR6. I would like it to work when the wipers are on slow, so I can switch the wipers on as normal (slow), then to use another switch to change them between slow-constant and slow-intermittent. I know many fellow 6 owners that would love this feature and indeed, I know many already have it.

 

I have bought a simple Nagares time delay relay which came with the wiring diagram I have attached below, but I know I need more than this. I have read all the posts I can find in the forum on this topic and there seem to be quite a few people who have managed to install intermittent wiper functions, but not one thread says exactly how they did it! I have also Googled this to death but cannot find a single piece of information anywhere that shows how to wire them.

 

I have done some research on the wiper motor wiring diagram and have deduced the following. When the wiper switch is in the slow position, it connects the Green (+ve when ignition on) pin 2 to the Red/Light Green pin 3 on the wiper switch. This provides +ve to the motor which is obviously earthed through the Black wire at the motor. When the wipers are switched off, the switch connects the Red/Light Green pin 3 to the Brown/Light Green pin 4 on the wiper switch. The Brown/Light Green comes from the motor and whilst the wipers are not parked, provides +ve feed which goes through the switch, back out of the Red/Light Green pin 3 to the motor providing +ve to the motor which is still earthed through the Black wire. However, when the wipers park, they trigger a switch in the motor itself that breaks the +ve feed to the Brown/Light Green pin 4 and instead connects it directly to the motor's Black earth. This means that while the wipers are in the park position, both the Red/ Light Green and Brown/Light Green are earthed.

 

All this is well and good but it means that in order to get the intermittent wipe to work, you not only need to intermittently provide power to the Red/Light Green, you also need to intermittently break the Brown/Light Green, otherwise (with the wipers in the park position) you would simply be providing power directly to earth. Not good me thinks.

 

So far, I have managed to install a switch which activates the delay relay. The relay has a positive connection to pin 4 (on the relay) and earth connection on pin 5. When I activate my switch, it connects an earth to pin 2 and the relay starts "clicking" every 5 seconds. From what I can tell with my multimeter, as the relays activates, it provides a short "on" every 5 seconds from pin 1 which is normally "off", and a short "off" every 5 seconds from pin 3, which is normally "on". So far so good. In the diagram, the "Switch" allows you to either include the delay timer in the circuit, or not.

 

Given my understanding about the motor wiring in a TR6, my plan is to cut the Red/Light Green wire at the motor and connect one end (from the main switch) to pin 30 on the (normally off) standard relay and the other end (to the motor) to pin 87. But I think I also need another normally on relay, wired in parallel to the normally off relay so that I can also wire the Brown/Light Green wire in a similar way. This will then mean that the delay relay when activated will not only provide +ve to the Red/Light Green but also break the earth going through the Brown/Light Green. By the time the delay relay switches off again, the Brown/Light Green will again be made allowing the wipers to park.

 

I am not great at electronics (as you can probably tell) but I am hoping that somebody can confirm my thinking is correct.

 

Thanks in anticipation!