Wipers | The Z Club of Great Britain


Discussion in 'S30 (240Z,260Z,280Z) Electrical' started by Rob Gaskin, Apr 3, 2014.

  1. Rob Gaskin

    Rob Gaskin Membership Secretary

    Just a heads-up in case anyone is working on their wipers.

    As some of you will know from my recent Thread I'm working on the wipers on my Blue car to get them working as best they can. I may do the upgrade to a Honda Wiper Motor (faster) one day but not yet, I'll see how these work first.

    I will post a full report in a few days but it has answered a few questions I had. I couldn't find the answers in Manuals (even Nissan) or on the US and Oz websites.

    Morbias I saw a post by you on one of the sites re yellow wire.

    What I have found with old cars is that they drive ok and can be modified and maintained to perform perfectly well for today's road conditions but it's the ancilliaries that are the weakness - lights, demisting, wipers, horn, window winders, door locks, steering column switch-gear, seat belts etc. These are not the 'sexy' things to work on and nobody notices them when looking at your car so they don't always get the attention they need.
    Last edited by a moderator: Apr 3, 2014
  2. johnymd

    johnymd Active Forum User

    Sorry to hijack a little bit but this is related to wipers. I've had an issue with mine since putting the car back together in 2009. They are a bit random in the way they work. For example. If i put them on speed 1 or 2 they work fine but when I switch them off they will sometime just stop anywhere and other time park in the upright position and other times in the correct position. Then if they have parked in the correct position, a few seconds latter they will then move to the upright position. If I go over a bump they will often do an intermitant wipe and stop in the upright position. Intermitent is also a bit random as it will sometime wipe once and other time several wipes then stop.

    I can live with this but anyone got an idea of where to look to fix this?
  3. Rob Gaskin

    Rob Gaskin Membership Secretary

    I must go out now John but the whole self parking process is something I've found out about.

    Must go.
  4. Nigel Brook

    Nigel Brook Active Forum User

    Rob: I presume you got the info for the Honda upgrade from the US z club site. If so you may have seen my post on there about compatibility and especially the mounting bracket which the US boys completly ignored ! Works better with the wiper motors available here. Couple of pics on there as well.
  5. Rob Gaskin

    Rob Gaskin Membership Secretary

    John, the first place I would look is on the motor itself. On the top of the 'gearbox' section there is a domed shaped cover with 2 wires feeding into it. These are connected to contacts inside which are operated by a cam. The cam opens the contacts when the wipers are in the parked position thus cutting drive to the wipers. These contacts are only in circuit when the switch is in the off position or during intermittent wipe.

    I would suspect the contacts are broken or loose causing erratic timing.. Do you have a spare (late year) motor?

    I will explain more about the wipers but the most interesting finding for me was that when the wipers are parking (switched off) the motor runs in the reverse direction and has a clever mechanism on the linkage which parks them in a position outside the normal wiping arc. I suspect most cars don't have this bit working correctly anymore. Did you ever wonder why the wipers do a wipe when you switch them off from intermittent?
    Last edited by a moderator: Apr 4, 2014
  6. status

    status Active Forum User

    Mine do that Rob,are they suppose to as both my 260's and both my 240's done it
  7. johnymd

    johnymd Active Forum User

    Mine have never parked in a different position from the normal wipe area so I guess it's not been working correctly since i got the car. I wondered if it was wired wrong as I did rewire this part of the loom. I'll have a play. Thanks.
  8. Rob Gaskin

    Rob Gaskin Membership Secretary

    John, if they work ok on continuous wipe then I reckon your wiring to the motor will be ok. The intermittent wipe gives them a pulse to get them off the 'park' position and then part of the self park circuit comes into play to stop them in the right position (but not fully parked).

    I suspect the cam contacts as mentioned earlier, or the 'tang' on the base of the disc which has the cam lobe on it is broken and allows the cam position to rotate freely so they stop wherever it stops (or start if you go over a bump). The easiest answer is to try a spare motor but you will need the late motor with 6 wires (not 5) in the connection block on the bulkhead or you wont have the intermittent facility.

    John, if you don't have a spare motor and want them to be reliable then if you cut one of the two wires to the domed cover on the wiper gearbox (not the relay on the motor body) you will lose the self parking etc but at least you can stop them manually where you want to. Do they ever keep running even with the switch off?
    Last edited by a moderator: Apr 4, 2014
  9. Rob Gaskin

    Rob Gaskin Membership Secretary

    Ok we have already established that S30s have different wiper arms right and left – the shorter arm should be on the driver’s side (RHD or LHD). The mechanisms are of course configured differently for different markets - note most manuals I have seen feature the LHD system.

    Also the manuals tend to feature the early non-intermittent wiper wiring diagram and motor. The non-intermittent motor has 5 terminals in the bulkhead motor connector; the later wiper has 6 terminals. If you fit an early motor to a later car the intermittent wipe only sweeps for the duration of the pulse from the relay i.e. not one complete ‘across and back’ wipe. There is no circuit in the early motor for intermittent operation.

    Wiper arms – I think these do not have splines when new. My wiper-arm splines are worn so I’ve tried to get some with very good (deep) splines without success. I did however buy a brand-new Datsun Bluebird wiper-arm off ebay to ‘check it out’. It didn’t have any splines at all and from what I can gather off the internet the idea is that the steel pivot cuts it’s own spines in the alloy arm when it’s bolted up tight. Other cars do this too eg Alfa Romeo.

    The pivots that protrude through the body can suffer badly from wear and thus give a sloppy wiper action. I bought two new ones from Japan but they are handed so beware – the driver’s side pivot has two posts for the linkages. One to transmit drive from the motor the other to transmit drive across to the passenger side. This is not obvious on the diagrams I have seen, they look as if both linkages attach to the same post. The two post are cleverly positioned to give the passenger side a greater ‘sweep’ across the screen.

    Wiper motor operation. The two speeds are achieved by using different windings in the motor. Stopping the wiper in the correct position (intermittent or off ) is achieved by the use of a cam that sits on top of the wiper motor gear wheel casing. As the cam ‘comes round’ during the intermittent wipe cycle or when switched off it opens a set of contacts which stop drive and halt the wipers in the correct position. Power is fed to these contacts even after you switch the wipers off in order for them to self-park. If the cam is loose or the contacts are broken/dislodged the self-parking will be unreliable.

    Note that self-park contacts are fitted in a cover which is clamped to the motor gear-casing. This cover can be rotated so the park position can be adjusted in theory!

    Final parking of the wiper arms. This is the clever bit which took me a while to work out. When the wipers are switched off the DC motor reverses it’s direction due to circuitry controlled by a relay strapped on to the side of the motor (this relay is used at other times too in the wiper operation). The linkage is attached to the motor via a short arm an eccentric cam bearing and coil spring. During normal operation the eccentric cam is in a position which has the effect of shortening the linkage, when the motor reverses the coil spring tightens due to the direction of travel, grips the eccentric cam, rotates it through 180’ and lengthens the linkage thus parking the wipers lower down the screen – clever eh? That’s why when switching to the off position the wiper always does a wipe – it’s to ‘park’ the wipers low down the screen.

    Now the problem is that on most cars (your’s? mine was) this coil spring will be broken and so the wipers will not park fully! If you position the wiper to park low down then this will become part of it’s normal sweep and so the other end of the sweep will be short!

    On the internet sites I’ve looked at nobody understands the purpose of this broken spring and because the wipers work with it broken it’s overlooked.
  10. Rob Gaskin

    Rob Gaskin Membership Secretary

    I will try to post some pics to make it easier to understand.
    Last edited by a moderator: Apr 6, 2014
  11. Rob Gaskin

    Rob Gaskin Membership Secretary

    Does anyone have a wiring diagram for the late 240Z wiper motor that they could share with me?

    I have diagrams for the early motor (5 circuit plug) but need one for the late (6 circuit plug) type. The extra wire is yellow.

    I'm interested in the complete wiring from bulkhead connector to and including the motor/self-park contacts and the relay strapped on to the motor.

    For info. the actual wiper MOTOR appears to be the same i.e. 3 brushes and the gearbox. It's the circuitry that gives the intermittent feature (together with the pulsing relay in the foot-well area).

    I reckon a 260Z diagram may be ok for my needs too. I know the 260 has a round plug at the bulkhead but the wiper motor may be the same.
  12. MaximG

    Z Club Member

    Hi Rob,

    I would have thought that only the one that transmits the action from one side to the other was handed? Is it possible that the pins could be pressed out and just swapped round?

  13. Rob Gaskin

    Rob Gaskin Membership Secretary

    By handed I meant that they are not the same each side. Also the double pivot one on the driver's side would be different for RHD and LHD markets I reckon (i.e. a mirror image of itself).

    Attached Files:

  14. MaximG

    Z Club Member

    Yep my thoughts exactly Rob. I,m just putting mine back together just for something to do to be honest. I also picked up one of the new pivots like yours as it seemed to be the most worn out of the two.
  15. andrew muir

    andrew muir
    Z Club Member

    Just swapped mine over, a subtle improvement!!:rofl:
    Where can you get the little pins for the wipper blades??
    One of mine is worn halfway through!!
  16. tel240z

    Z Club Member

    Im not to convinced about your parking lower down the screen rob unless the motor goes forwards and reverse on normal wiping ?? As the rotational effort of the motor drive arm will send the wipers full sweep back and forth as your aware i have totally re wired mine (tricky and probably wrong) but concluded that the dc motor needed to be shorted out momenteraly to brake the wipers at rest or the inersia would let them park anywhere depending on a wet or dry screen

    Sent from my GT-I9505 using Tapatalk
  17. Rob Gaskin

    Rob Gaskin Membership Secretary

    I am correct Terry, believe me. The motor spins one way until it is switched off and then reverses. The clever but simple spring and cam mechanism extends the length of the linkage by 2 or 3mm to park them! On both my cars the spring was broken (but sorted now) and I suspect it is on most cars. Also both motors reverse when switched off, honest. The voltage polarity to the motor is reversed. I just find it interesting.
  18. Rob Gaskin

    Rob Gaskin Membership Secretary

    I'm doing a conversion to a Honda motor to improve wiper speed (not that I ever drive it in the rain :eek: ). Anyway there is lots about this mod on American sites. I've got the wipers working ok and self parking however I've got a problem which doesn't seem to be covered on any sites. The wiper motor spins in the opposite direction so during normal operation the 'sweep' is lengthened due to the mechanism mentioned above. When parking they stop higher up the screen! Anybody done this mod?
  19. franky

    franky Active Forum User

    Are they spinning the other direction because the instructions are LHD?
  20. Rob Gaskin

    Rob Gaskin Membership Secretary

    Well I've done the Honda upgrade this week and it's a big improvement. Not straightforward but worth the effort. I'll do a write-up soon with video links. Basically on a wet screen the fast of the Datsun motor is equivalent to the slow of the Honda. On a dry screen (ok why?) the Datsun wipers almost stop, the Honda wipers are not so affected.

    Last edited by a moderator: Jul 13, 2017

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