AndrewMAshton Posted August 16, 2021 Report Share Posted August 16, 2021 Hello, searched the forum but no reference to my setup which I suspect is not standard, my wiper switch has three contacts on the rear, two joined and one single, so effectively two contacts. The wiper motor has two lucar contacts plus earth, the wiring diagram shows three separate contacts on the switch. I am struggling to see if any of the connectors, switch or motors, are marked or identified, I can't see anything. Without the benefit of a setup that matches the wiring diagram my thought is the supply goes to one of the paired connectors, with the other paired connector providing the park supply for the motor, the other switch connector goes to the motor for normal use. The other question is which of the two motor connectors is park and which is for normal use, hopefully the above makes sense, thanks as always, Andrew Quote Link to post Share on other sites
RogerH Posted August 16, 2021 Report Share Posted August 16, 2021 Hi Andrew, that all sounds very odd. Do you know which motor you have? The DR3A is a single speed and has 1/4" spade fittings on the back of the motor - +12v from the green wire and the green/black goes to the switch The DR3 is a two speed motor and should have three wires (Green +12v) Green/Red & Green/Brown going to the switch there is also a black earth wire. The switch receives the G/R & G/N wires and switches them to earth (either one or both) The parking is controlled by the red wire on the top if the wire motor - this shorts to earth and is controlled by a copper track inside the motor. Roger https://www.mmoc.org.uk/messageboard/viewtopic.php?t=63515 Quote Link to post Share on other sites
keith1948 Posted August 16, 2021 Report Share Posted August 16, 2021 Hello Andrew The 2 speed wiper circuit must be one of the most confusing. Others have both wires for fast when on mine both are for slow. There is an article written by Alan Turner where he has the fast wire connection as brown/green and both as slow. I'll just tell you what I have on my 4A and it works fine. There are 4 wires exiting the loom next to the wiper motor. The green wire route is from the fuse box to the voltage regulator in the right hand drivers footwell on the right side wall. There is a double connector. The green wire continues from that connector to a double bullet connector that appears out of the loom above the steering column. (a bit hard to find) It then continues and appears as one of the 4 wires next to the motor. This is the +ve supply from the battery. The 2 wires coloured red/green and brown/green connect the motor to the switch on the dashboard. The switch has 2 positions. On my car the first position of the switch connects the red/green to earth for fast speed and the second position connects both the red/green and brown/green to earth for the slow speed. However NOTE that I have seen circuit diagrams that say the brown/green is the fast wire. To check you have the correct wire for fast, remove the end of the motor and look to see which wire connects to the self park wire. In mine this is on the right as you look inside. The red/green and red self park wires are soldered together. The brown/green connects to the field winding on the left. Do not connect only the brown/green (in my circuit) to earth for slow speed or you will burn out the wiring. If in doubt connect both red/green and brown/green to earth together to give you the slow speed. There is a black wire from the switch that is the earth wire. Confusingly this also emerges as the 4th wire next to the motor and this is earthed to the bodywork next to the motor. On mine there is another black wire that goes from the end of the motor to the bodywork. This is the earth for the self park mechanism. The red wire on the motor itself is the self park circuit. The motor self parks on fast speed hence the wire connected to the red inside the motor is the fast wire. Hope this makes sense Keith Quote Link to post Share on other sites
tthomson Posted August 16, 2021 Report Share Posted August 16, 2021 If you are using the pull switch normally installed on TR4As, then the switch connections are shown in the attached file. Search for Alan Turner on this forum to get more detail on the wiring. Lucas 34477 switch.pdf Quote Link to post Share on other sites
AndrewMAshton Posted August 18, 2021 Author Report Share Posted August 18, 2021 Hello, many thanks for the responses, it looks like I have a hybrid system as it does not correspond to the advice, hopefully the pics will add clarity, my switch is off/on only yet the motor has two spade connections and an earth, Quote Link to post Share on other sites
RogerH Posted August 18, 2021 Report Share Posted August 18, 2021 Hi Andrew, the switch looks like a heater motor switch but should still do the job. Your motor is a single speed DR3A - the two spade fittings - 1- Green (12V in) 2 - Green/Black (to the switch). The earth wire is simply that. Roger Quote Link to post Share on other sites
RobH Posted August 18, 2021 Report Share Posted August 18, 2021 (edited) Andrew, the power to the wiper motor does not come via the switch - it goes direct to the motor from the fuses. The switch is in the earth line from the motor as is the self-park device internally. While the switch is made the motor is earthed and runs. When you open the switch, the motor continues to run until the self-park contact also opens to remove the earth. There is always power to the motor. Diagram here ( I think Rodger may have got the connection numbers backwards ? ) https://www.mgaguru.com/mgtech/electric/pdf/2spd_dr3a2.pdf Edited August 18, 2021 by RobH Quote Link to post Share on other sites
RAHTR4 Posted August 18, 2021 Report Share Posted August 18, 2021 Hi Andrew, The Wiper motor 75442 is a single speed unit and only appears to have been used in the Sunbeam Alpine MK II and the gear wheel inside would not have been correct for a TR4A so presumably a previous owner has changed it for the correct 120 degree type. Regards, Richard Quote Link to post Share on other sites
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