Jump to content
SAU Community

Recommended Posts

G'day , Iv'e tried changing the switch but same thing !! I know the other switch I used is good but no luck. Was thinking it might be a relay and looked on YouTube but didnt really find anything - looking at the fuse boxes and can't see anything about wiper fuses or relays. The only thing that comes to mind is something I saw on Y/T was some sort of fuse box with a relay or 2 but the dude says its an unserviceable part , it was off a 2003 Maxima - thats the closest Iv'e come 

G'day sorry I had a data issue so couldn't reply until now . I doubt whether its the wiper motor as it works on high/fast no problem just no slow or intermittent . I feel as though it might be a relay but can't even see a wiper fuse on the fuse box diagram/covers. A YouTube video showed a control board with some fuses and a relay or two but the guy said it wasn't a serviceable part but can't remember where its located . maybe near the interior fuse box in the kick panel . I'm so so with wiring diagrams - understand  simple stuff and can operate a multimeter when following instructios but interpreting the data/results is another matter . If I'm guided what to check and what to expect I'll be able to get somewhere .

( This is my 1st question on the SAU forum and I really appreciate the response and dedication shown by the SAU family , it is the best:thanks: )

Thanks @sonicii I reckon thats where I have to investigate. This looks like the unserviceable thing I mentioned that I saw on YouTube - where do I find this fuse box or power module whatever its called ?? Do you know if these relays can be tested and replaced or if you have to replace the whole module ?? 

These diagrams have got a *lot* better since the R32 days.

From that pic it looks like the wipers will be hi only if the "front wiper high relay" is stuck closed. It looks like it physically lives inside the PDM (power distribution module) which is probably a fuse box under the bonnet. If you can find a relay marked that way unplug it and see if you lose hi and low wipers. If so, try and replace the relay with another working one that is physically the same (just don't use the front wiper relay, it is also required)

It can be the wiper motor failed also. As you may see from the diagram, there is an input for low speed and one for high speed. They go to different windings in the motor. The high speed one could be good while there could be a problem with the low speed one. That problem could be anything from a broken wire to a burnt winding.

The question here is, does it work on hi even when you switch it to low, or do you have to switch it all the way to hi to get it to chooch?

All these things are testable by direct powering the motor (you give it an earth and power to the winding you want to run), probing with the multimeter in the places on the wiring diagram where you're supposed to have 12V (constant), 12V (when running), earth (constant, or when running, depending on whether the circuit is supply side switched or earth side switched. This one is supply side switched, so the is constant, and we know it works because the hi speed works.

4 hours ago, V35Newbie said:

where do I find this fuse box or power module whatever its called ?? Do you know if these relays can be tested and replaced or if you have to replace the whole module ?? 

I believe they are tucked in a really awkward spot behind the battery so you need to remove a few trim pieces as well as the battery to get to it.

As far as I know the relays can be unplugged and tested, I'm not sure how hard it is to source replacement relays though.

 

Have a look here -

 

Where to begin - As the comment says in the pic from Sonicii I appolgize for not being able to find previous posts in the forum but I'm still trying to get my head around navigating SAU site ,sorry guys your patience and tollerance for a newbies ignorance is outstanding :worship:

Thanks Duncan I wish I had your understandig of wiring diagrams , I get what your saying sort of. At the moment I have nothing in the intermittent position , nothing in low position only high on high and if I pull back the switch for a manual squirt and wipe it only squirts - no wipe . Tomorrow I will try and see if I can swap relay with another fom a different system just hope its not a multi coil relay.

Next will be to test the motor , THANKS GTSBoy :91_thumbsup: I had no idea the motor had more than 1 winding . As stated above the power I'm getting - Only high in high position , nothing else except squirt. Thanks for the instruction on what to do with the multimeter - I don't know what to set the meter on with the dial ? :35_thinking:

Sonicii , appreciate the photo - I have located that box behind the battery yet to open. Hope you're right about being able to service the module 

THANKS SO MUCH guys , exactly what I meant about a Fantastic SAU Family :17_heart_eyes:

It's probably worth watching some basic multimeter videos on youtube. 99% of the time you will use one of 2 settings:

Continuity - when you touch one probe to one end of something and the other probe to the other end, it beeps if they are connected. This tells you if a wire is broken internally, if you have 2 ends of the same wire, if a switch is working etc

DC voltage 0-20 - This measures the voltage between the probes, so you might use it to see if you have 12v somewhere by having the red probe on whatever you are testing and the black one on bare metal in the chassis (generally a bolt). Don't let the probes touch while doing this as you can cause a short circuit.

With the wiring diagram it might help to print it and draw on it. The relays show a coil and a switch. When you have 12v across the coil, the switch changes across. Because we can see 12v on one side of the coil from the battery, via the ignition switch, we know that the control unit triggers the coil by providing earth/negative.

So....when the control unit earths the Front Wiper Relay, battery power is provided by 20A fuse #73, through the Front Wiper Relay to the input of the Front Wiper High Relay. If the control unit is sending the High signal to the Front Wiper High relay, that power flows through the relay to pin 31, the to the wiper. You know this is working because that is all you get.

Alternatively, if the control unit is not sending the High signal, the Front Wiper High relay is meant to be set to the Low side and providing power to pin 21. Most likely this is not working in your setup (noting as GTSBoy said it could be a wiper motor issue as well, or the switching). The correct way to see if it is the unit or wiper is to see if you have 12v at pin 21 when the wipers are set at low, but the easy way to check that is by just swapping in a good relay as that is the most likely thing to fail (because relays have a mechanical part that moves thousands of times in it's life), but of course any other part of that whole sequence could have failed, including upstream to how the switch works....you just need to follow it through each step.

Having said all that, since you said it doesn't work at all in Low or Intermittent, it may well be a motor issue (I though you said you get high no mater what you set it on). That pretty much narrows it down to the High Relay, the Relay's socket wiring or the wiper motor itself.

  • Like 2
  • Thanks 2

Thanks Duncan this will give me more confidence to use a multimeter - I just ordered 1 from Ebay .

Before I start poking around something I know nothing about a little update ; Super confused !!

I just run the self diagnostic check { push the button 10 times in drivers side door jam } here I get low & high wiper speed , putting lever up to Mist setting - get nothing , but when I pull back on the lever I get a squirt and a few wipes on low. Sorry earlier I said I only got the squirt when pulling back the wiper lever and forgot to mention anything about the mist setting

Well, if hi and low both work in diagnostic mode, that sounds like a switch issue, but you said in first post that you had swapped the switch with a known good one, so maybe it is a swtich wiring issue. I would have expected a modern car used CAN rather than separate wires (also because the excerpt sonicii posted only talked about the control unit to PDM to wiper motor).

If you can dig out the switch to PDM wiring we might be able to understand more

I would agree with Duncan.

Not sure how easy it will be to diagnose if you aren't familiar with electronics and use of a multimeter, but these 3 pages might help a bit to troubleshoot the switch.

As you can see, only the washer pump is operated directly from the stalk switch, the rest are just inputs to the BCM, which controls the motor.

Since there are diodes in circuit with each switch position, you will need a multimeter on diode check position.

But normal continuity or ohms setting will be fine for the harness testing.

ww1.pdf ww2.pdf

ww.pdf

Edited by sonicii

Thanks guys you's are a wealth of information I just wish I could get my head around this electrical stuff - mechanical stuff I understand no prob !! 

I've accessed the fuse box next to the battery in the photo from Sonicii and was about to start pulling relays out to manually test each one coz I can't even tell which is which but thought thats probably a waste of time as I had both speeds working in the self diagnosis test - would that be right or should I pull em out and check

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Oh, that's grim. Something bad has been happening there.
    • Put an endoscope down the hole and saw this. Not quite all around the bore but a good 60% at least. Chin to the chest and towards further disappointments I guess.
    • 2 does "sort of" applies, maybe......but looking at what parts would be needed for the swap to get engineered, registered, and insured, and basically that's everything under the car, the modifications the make it legal would be problematic and horrendously expensive, all for a street car that just cruises around and hits a few twisty roads on the weekends Also, from looking at the NSW rules and Regs, with all modifications that is required just to make the car safe and not twist itself to pieces, and then actually get registered for street use, may still be impossible nowadays As for 1, when you add in a fresh engine, fresh transmission, rear cradle and diff, tailshaft, suspension, brakes, cooling, and all the other fabrication required, your probably looking at up to $100k to do it right, all for a 20 year old MX5 that is over engineered and you would never be able to actually use the power it has on the street, much like your beastie, which I love, but you actually track that thing and can use all of its powers in anger, in a safe environment  Hell, the old Bogan Cruise Ship had more power than I could use on the street, and in hindsight, I went a bit silly on that thing, it didn't really need the 500hp it had for what I actually used the car for, it was fun, but basically unusable on the street if you value your licence  As for cams, yeah, I'll probably book it in for them to get installed and tuned soonish, like next month after MX5 Mania are back at work....... and yes, I've already sent a email to bin the turbo quote and quote instead to install cams and a new Fluidampr balancer that will suit the 2.5 better than the OEM 2.0 balancer that is swapped over for the 2.5 install, as the balancer needs to get pulled to time the cams it's a while your in there sort of thing I did think a bit about flex fuel for a laugh, but being na, and no where really around locally anymore to get E85, I've binned that idea, so no sweet sweet corn smells are set for the car I wish E85 was more of a standard fuel, it's better for the environment, better for tuning, plus that sweet sweet smell we all love As for fitting in the family, that's not needed, as everyone in the family already owns a car that can seat 5 humans comfortably enough, the MX5 is "my toy" As for buying a car that is already built, nah, I would rather pick and choose my parts, I enjoy the process, and in the big picture, the additional cost is well worth the enjoyment, and the occasional frustration, I get out of doing it, albeit with other people spinning the spanners, and me, just paying the invoice 🤣
    • Excuse me, but 2) does apply 1) Would also apply if you consider how much is spent in the alternatives. Also there's the option of 3), buy one pre-built that you can put your family in (it's me, it's my car)   That said, I went on a ~500km drive the other day. I didn't use anything more adventurous than 3rd/4th gear at about ~3000RPM and 50% throttle and I was going as fast as anyone has any sense doing on a public road, with enough grip to the point where I didn't want to go any faster. I was obviously under the limit of the current car etc etc. MX5 with 2.5 N/A to achieve the same speed would be more fun for any road scenario. Maybe consider cams. I wouldn't boost it. The use case is just not there and it won't actually make the car more enjoyable unless you really do plan on wringing gears from 1st to 3rd (at least) at 100% WOT on a public road to 150+kmh.
    • Great if: 1. You had all of the money for everything else that is required  2. Lived in a country where you could actually do this and drive it legally on the road Sadly, neither applies to me As for the turbo, I am having second thoughts, mainly for engineering/registration legality reasons and insurance  Not saying I've finished doing stupid things that I probably should do to the MX5, but boost, and V8 engine swaps isn't on the cards Strange, but true 
×
×
  • Create New...