Wipers only work on slow speed

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jookul100431

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Wipers only work on slow speed

Postby jookul100431 » Sun Oct 06, 2019 12:31 pm

Hi Just need some help here if possible.
My windscreen wipers only work at slow speed
Fast speed and intermittent do not work.

Some things I have done to date
1 test both relays in the bench and they are both switching so I am thinking they are ok
2 I have also swapped these relays with each other and no change
3 I justed installed a used stalk and no change
4 with the live data from my reader I can see that when I operated the switch all the function seem to be seen buy the live data so I am assuming the switch is fine

Wiper washer work correctly and the pull forward for one swipe is ok and the wipers park correctly.

I can see an error codes which say the slow high speed relay circuit is short circuit to ground and I can't seem to clear that error

Has anyone any idea. Next easiest thing to do is replace both relays but the are 40 Euro each and don't want to waste that money.... I hoping it's not the control unit

I have spent over 3k on various repair since I bought the car 3 months ago and am getting a bit distracted so want to try and be a bit more accurate with diagnosis first so any help would be appreciated

Many thanks every I have got good support and advice from the club since joining so really appreciate it

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J44EAG

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Re: Wipers only work on slow speed

Postby J44EAG » Sun Oct 06, 2019 7:08 pm

I`d suggest a serious check of all -Ve grounding cable points. Two behind the headlights and one in the area of the pollen filter unit.

Used relay units have previously been supplied to me by Eurojag. Details on the internet and in our magazine. Prices are very reasonable.

Mike
X350 Co-ordinator

2004 XJR

PaulGover

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Re: Wipers only work on slow speed

Postby PaulGover » Sun Oct 06, 2019 7:13 pm

...
I can see an error codes which say the slow high speed relay circuit is short circuit to ground and I can't seem to clear that error
...
If the diagnosis is correct, you should be able to locate short with a voltmeter and a wiring diagram - my guess would be some damaged insulation, or something full of water.
1981 XJ6 Series III - strictly XJ6O2 - dissolving in the rain
1986 XJ6 Sovereign Series III
1991 XJS V12 "facelift"
2008 XJ TDVi

jookul100431

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Posts: 33
Joined: Wed Aug 07, 2019 12:00 pm

Re: Wipers only work on slow speed

Postby jookul100431 » Tue Oct 08, 2019 8:50 pm

so a quick update.... It turns out that the chnage out of the wiper stalk has improved the situation but not fully and today I got two new spurious relays from truck electrics and when I installed them no difference....

1) Replacement of the wiper stalk brought back the intermittent wiper operation.
2) high speed not working
3) have not tested the auto function since replacement of stalk.

I tried to do a bit of metering today.... and on the on/off relay R4 i pulled the relay and measured 12v across contacts 1 and 2. the strange thing is this voltage was always there no matter what position the wiper stalk was in ie from completely off to position of high speed. I am a bit confused at to why this 12v was always there but this relay is working and you can hear and feel it switch when the wipers come on

I did the same for the slow/fast relay R8 (pulled out) and the voltage across contacts 1 and 2 were 1.5V. I presume this should be 12v as well and hence that is where my short is.... also when i put the stalk to high speed i did not hear or feel the relay switching. I don't think the wiper motor is the problem as that is on the load side of the relay and I think my problem in the control side (coil not energizing)

So I need to track this down and really not looking forward to this as if this is a broken wire it could be anywhere. I believe there is a ground point under the front distribution box and I am hoping I may find something obvious there

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J44EAG

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Re: Wipers only work on slow speed

Postby J44EAG » Tue Oct 08, 2019 9:54 pm

Someone will have to confirm this idea. Much of the switching is completed on the -Ve side of the circuitry.

Mike
X350 Co-ordinator

2004 XJR

jookul100431

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Re: Wipers only work on slow speed

Postby jookul100431 » Wed Oct 09, 2019 6:09 am

That would be great is some could as that is part of my confusion. The on off relay is also switched on the negative _Ve side and that continually had 12v on across the connector base when I metered it out across pins 1 and 2 I was not expecting to see that voltage there all the time. Even with the wiper stalk in the off position it was there. But that really seems to be fine and work fine....maybe by putting in the relay that changes things a bit and I of course could see this as I couldn't get access.

Hopefully so one can point me in the right direction

PaulGover

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Re: Wipers only work on slow speed

Postby PaulGover » Thu Oct 10, 2019 12:29 pm

Looking at the circuit diagram, both relays get a +12V feed to pin 1 from the front fuse box. The relay coil (and a protection diode) sit between pin 1 and pin 2 ; pin 2 is connected directly to the front electronic module (FEM). So as Mike says, it's negative switching, and the FEM pulls pin 2 to ground to energise the relay coil. Pin 1 should always be +12V relative to earth - check that with your meter.

Pin 2 is the FEM output. For the slow/fast relay, according to my 2008 wiring diagram, it's a blue/green wire connected between the front distribution fuse box (where the relay is) pin 8 of a 10-way black connector and the FEM pin 17 of a black 22-way connector; AFAIR the FEM is at the bottom of the LH 'A' post. Its operation is described as "WIPER FAST / SLOW RELAY ACTIVATE: TO ACTIVATE, FEM SWITCHES CIRCUIT TO GROUND".

Check VERY CAREFULLY the voltage to ground at at the relay socket pin 2, the 10-way connector pin 8 and at pin 17 of the 22-way connector. (Any mistakes might blow the FEM.) You may be able to remove a connector and insert a needle into the wire into its pin, or into the back of the connector and connect your meter to the needle to read the voltage (take care not to short it to earth). My guess is either a bad connection (low voltage) between the front fuse box and pin 1, or damaged cable between pin 2 and the FEM, or a duff FEM. According to the diagram, it's a single wire, no splices or other connections.
1981 XJ6 Series III - strictly XJ6O2 - dissolving in the rain
1986 XJ6 Sovereign Series III
1991 XJS V12 "facelift"
2008 XJ TDVi

jookul100431

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Posts: 33
Joined: Wed Aug 07, 2019 12:00 pm

Re: Wipers only work on slow speed

Postby jookul100431 » Sat Oct 12, 2019 5:51 pm

Hi Paul

Thanks for the detailed note...only saw this now. But I was trying to fault find todau and reconfirm what's good and bad...after my work today. I'm starting to think the same as you...I got an older wiring diagram 2006 and was using that all the voltahes and resistance measurements on the fast slow relay make sens except pin 2. If I measure between pin 2 of the slow fast relay and ground I get approx three volts... I have swapped out the obvious parts and not difference...both relays and wiper stalk and I remove the connection to the rain sensor during the process to c if that makes a difference....I didn't look at the FEM as didn't want to go pulling too much apart... Also I manually jumped the slow fast relay the wipers went to high speed so I'm thinking that's ok as well....only options left are wiring short or break Faulty FEM or fusebox my machine knows a good auto elect so I'm going to bring it too him when I can..... I seem to buying many different parks to try and fix this but not getting anywhere.

I also noticed that the front fusebox has a very low level ticking noise coming from it. It's hard to hear but it's there... I have no idea if this is a problem or not...if anyone knows please let me know

Getting a bit dishatend with the car at the mo....a lot of money spent trying to put various thing right. I have to say this is one of if not the most troublesome car I have owned. And I have had my fair share of luxo barges in my day....very tempted to go back to Merc.... As much as I want to enjoy the Jag...it's not making it easy. I'll stay with it a bit longer but Patience are running thin🤪🤪🤪

Thanks against n for all the support

jookul100431

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Posts: 33
Joined: Wed Aug 07, 2019 12:00 pm

Re: Wipers only work on slow speed

Postby jookul100431 » Sun Oct 20, 2019 9:17 am

So where am I now

Mainly from the advice of many people from another forum I decided to disassemble the front 3 earth points to see if this would help my problem. Though I mostly believe my problem is as Mike says. .or one of those three issues and in hindsight I should have look at this first before I tackeled the earth studs....any not to my surprise after doing that no difference to the problem. What did happen was that one of the right hand ones broken when tightening back oup the nut so spent a bit of time repairing that...wasn't happy when that happened. So all I really got out of my time is problem not fixed and a broken earth stud

So what is the lesson learned... And this is a lesson learned over many years of using general forums. There is a lot of advice and help out there. But you have to be careful with what I take on board and temper that with you own situation. Following my own fault finding and Mike advice on this issue. I had a strong feeling that earth points were not my problem here or at least the front 3.

I joined the club and this forum as I felt felt I stood a better chance of getting solid help and advice rather than from a general one and I think this is true for me. People he seem to really love these cars and know them well. For me I'm sticking here with a eye on the general ones but I think I'll be staying here for my main advice and support

Thanks again everyone for the continued support and help. As I work through the fixes on the car..

On the plus side after doing all of that I did noticed that my passenger puddle lamp is working. Wich I never noticed before so maybe something good came out of it


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