Jump to content

Indicators, not


JohnD

Recommended Posts

I've got the new bonnet back onto SofS and the lights wired in.  They all work!

Or, rather, the indicators worked.    They flashed, both ways, but when I tried them again, nothing.   

I've tried to trace the fault, but there is power to the  fuse box ( I replaced the original with a six way one, with one fuse for the flashers.  From there it goes to the Flasher unit, so I diagnosed a faulty unit, but a new one makes no difference and there is NO power getting to that.     Broken wire somewhere?

John

Link to comment
Share on other sites

Are the bulbs filament types and do they look ok? Had the fuse blown? If they worked once and then stopped after that, I would be checking the fuse first and then if that's in tact, seeing if a piece of wire or connection acted as a fuse and sacrificed itself...

A good multimeter helps you check continuity and also test the wires for excessive resistance. It sounds like you're using one already if you have confirmed power at the fuse, if there's nothing in the circuit between fuse box and flasher relay then sounds like you've found the problem wire. Check it for resistance, if it's broken it should show on the multimeter.

Edited by RichardB
Link to comment
Share on other sites

As an aside on electrical fault finding on a car, a multi-meter is not always the best option.  The problem is they draw a tiny amount of current and so can tell you voltage is present  even when there is a very bad connection.  In practice you can find the majority of faults using a small 12v incandescent bulb with wires attached.  The advantage of this is it does draw appreciable current so will readily show up bad connections. 

  • Like 1
Link to comment
Share on other sites

Hello John

                  A bit to much Vino after a day out with other old buggers! 170miles but a good breakfast and 2 coffee and cake stops plus a narrow guage railway

God it's hard work enjoying yourself! and this was mid Wales so views to die for at times! (Well I think so and it was my route and they do not have to come but the buggers keep turning up?)

But your problem maybe bad earth? just guessing(Vino Again!)

Link to comment
Share on other sites

None of them work, Roger.   If one wasn't earthed would that jinx the rest?

Gotta check that resistance, a la Richard.  

Got the covers on those bonnet holes.    With the teardrop bonnet bulge, it looks as if I have an enormous V8 under there!   Send you a pic later.

 

16940869952651636189576493763292.jpg

Link to comment
Share on other sites

Colin, I think it must be between the fuse box and the flasher unit.  After Richard I checked continuity on what should be the live wire - there ain't none.      

Rather than try and trace a broken wire or connector, through the bulkhead where they all come together like mating snakes, I think I'll just run a new one and disconnect the old ends.   But currently, I'm fitting a passenger seat!    No, I'm not going soft in't old age, I'm off to Kop Hill next weekend, and part of their charity fund raising is to offer rides up the hill.   So an old seat and harness, superannuated by FIA dictat, but fully functional, is going in.   Hope I get takers - I might get an extra run!

John

Link to comment
Share on other sites

I ran a new wire through the bulkhead to the dash, but the flasher relay is about as hidden away as Shangri-La!   I have to lie on my face and look up l the A-post to find it.

So, I bought a "three pin flasher relay" and fitted it on flyer leads on a relay block on the dash.   I now have live battery volts to the relay!   But no indicators.   

The original relay has the power input  (G), a output to the jewel light on the dash (P)  and an output to the indicator switch on the steering column (L).  I bought a new Flasher relay with terminals labelled 31, 49 and 49a.   49 is the power input, 49a is to the switch but 31 is the Earth?!?!?

And it doesn't work!   Do I need a different relay?

John

Edited by JohnD
Link to comment
Share on other sites

Electronic flashers usually need an earth connection while the old bimetallic ones did not.  If the new one has no connection for the tell-tale it is the wrong type for your car.  

Sounds  as if you need something like this:

https://www.classiccarleds.co.uk/products/12v-electronic-indicator-flasher-relay-classic-car-with-oe-click-x-l-p-2-3-pin

Link to comment
Share on other sites

RR,

That requires a separate earth, and as well has a very different shape and look to most relays.  Call me pernickety, but is there an ordinary, square cube relay with no external earth that will do?   

EG Lucas SFB190??? 

See: https://www.abingdonmgparts.co.uk/product/lucas-relay%3A--various,-lotus/sfb190lucas?gclid=CjwKCAjw6p-oBhAYEiwAgg2PgqjyQUKmgoMJUNHh1Q58wTvZ0RToh73279yLPPhznXwztpBzQwDWURoC4psQAvD_BwE

Thanks!

John

Edited by JohnD
Link to comment
Share on other sites

All electronic relays will require a separate earth John.  The SFB190 has the same connections as the one you tried with no pin for the dash lamp.   If you want a square electronic one, this will do what you want but it needs that earth:

https://www.autoelectricsupplies.co.uk/p/12v-electronic-4-terminal

Your original flasher was obviously a bimetallic one but they are not common in square cans - usually they are round like this

https://www.carbuilder.com/uk/flasher-relay-3-pin-with-warning-light-feed

 

 

 

Edited by DeTRacted
Link to comment
Share on other sites

10 hours ago, DeTRacted said:

All electronic relays will require a separate earth John.  The SFB190 has the same connections as the one you tried with no pin for the dash lamp.   If you want a square electronic one, this will do what you want but it needs that earth:

https://www.autoelectricsupplies.co.uk/p/12v-electronic-4-terminal

Your original flasher was obviously a bimetallic one but they are not common in square cans - usually they are round like this

https://www.carbuilder.com/uk/flasher-relay-3-pin-with-warning-light-feed

 

 

 

As DTR and RR say.

The electronic relays all require a separate earth John.

Link to comment
Share on other sites

Thank you, DTR, RR and Colin!

The Common Room of Sideways U and the Dept.of Electrical Engineering have, as usual, most usefully informed me!

My wish for a 'cube' relay is because I already have some mounted on a rack on the dash, and I fear that a round one won't fit there.

The 140103 looks ideal and even I can fit an earth lead to it!

 

Thanks again!

John

Link to comment
Share on other sites

And, while I'm ordering new electrical parts, I have a number of other anomalies that fox me!    I'll be grateful for other's thoughts

This is a race car.  It has no conventional ignition switch, but does have a master (FIA) cut out that disconnects (or connects!) the whole loom from the battery.   I have divided  many of the functions of the 'ignition switch' and wired them into a bank of toggles on the dash, "Lights", "Rain light", "Pump 1" (lifter fuel pump to the swirl pot), "Pump 2" (main high pressure fuel pump for Pi) and TWO "Ignition" switches.     The fan switch is also on this bank.     The "Ignitions" are wired in parallel as I once had one burn out in a race, which sort of stopped me!  I thought that two would share the load!   All the toggle switches are the type that have a small diode in the tip, that lights up when it is ON.

1/ The diode in "Ignition 1" lights up when it is OFF! (and the FIA cut out is turned ON). This has happened while I was rebuilding the front end, not before.   I replaced it, but the new switch does the same. 

2/ The diode in "Ignition 2" never lights up, OFF or ON.   

3/ Some of the other diodes never light up, OFF or ON.

These light-up toggles all have an earth connection, so that the diode is earthed when it is ON.    I have wired these earths in series, using thick (8-12A cable, can't remember)  multi-core, to a substantial body earth.

Do these switches diodes go Phut?     I replaced "Ignition one" to no avail.    Is it worth buying a new set of switches, in the hope that they will light appropriately?

Any ideas about why the diode on "Ignition 1" is always ON, when the switch is OFF?

Thanks,

John

Link to comment
Share on other sites

The LEDs might indeed go 'phut' if there are large voltage spikes on the wiring. Quite possible depending on what you have in the way of ignition source and alternator. 

The switch diode is always earthed as it is connected between the output terminal and earth.  Operating the switch puts supply on the output and diode. 

If you have two switches wired in parallel to the same load, operating either switch will light both diodes. Similarly if there is residual voltage on the circuit being switched, the diode will light even though the switch is off.   LEDs don't need much current. 

As RR says, a schematic will help. 

Link to comment
Share on other sites

Sorry, guys, I'm confusing myself, you and different threads!   Please see my latest post on the dashboard anomalies at "Post Truxton Post Mortem" for wiring diagrams!   See: Post-Thruxton Post Mortem - Page 12 - General TrackDay and Race Prep - Sideways Technologies (sideways-technologies.co.uk)

Inspired by your advice, I've pursued the volts through the system.     Thank you, DTR, I got a 4 terminal flasher unit and gave it an earth,  Testing with a spare LED as a test light, I get flashing from the output terminal.   I then went to the steering column and saw flashing from the other end of that wire, AND from the wires that go towards the indicators.

Then I went to the new bonnet, and the multiway connector from the loom that suits on the bonnet hinge.     This is with the side lights on, and shining, but no indicators, and where logic avalanches into bizarre.     The Green/Red and Green/White wires that should go to the indicators had no volts at all, but the RED wire that should go to the side lights flashes!     But the side lights are shining steadily.

This is at the on-board side of the multiway connector, so it can't be that I have misconnected the wires to the bonnet lights, can it?

Not Confused dot com, just Confused, DoH!

John

 

 

Link to comment
Share on other sites

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
×
×
  • Create New...