406 Hdi electric noise

[Peter.N.]

My wife left the lights on and ran the battery flat, it recharged OK except there is a high frequency whine coming from the back, its so piercing that she won't drive it. Its coming from a box marked 'Ryder smart 7 bypass' inside the o/s rear wing which seems to be connected between the rear lamp wiring and the tow hitch power supply. I can probably do away with it if necessary but will probably loose my towing supply in the process. Can anyone tell me exactly what it does and what might cause it to scream at me, there seems to be an awful lot of electronics in it for a simple flasher repeater.

Peter

[spider]

If its a really high pitched noise its probably at a guess a DC/DC converter and you're hearing the coil "whine" . It may shut up after a while though.

I would guess these things are needed on plexed cars with third party towbar electrics to avoid any concerns.

Its not the 'tell tale' bleeper for when a trailer is attached is it ?

Do you have a trailer or something with electrics you can plug in temporarily to just see if it shuts up ?

[Peter.N.]

Hi Andy

It really is a loud noise, my hearing is deteriorating but even I can hear it, my wife can't stand it. Its like being in a shop full of 405 line televisions - although I don't suppose you remember those This car is not fully multiplexed it has the old style stalks. I don't have anything to plug into it unfortunately, I borrow a trailer occaisionally but don't really want to go to those lengths.

Peter

[spider]

No I don't remember those, I'm an 'M' reg

I'd consider unplugging it if you do not plan on towing often if that's possible to determine what will go awol without it. I did think about split charge (you have twin electrics) although I'm not too familiar with this setup really other than knowing its a couple of relays.

[Peter.N.]

I go back to the days of 9" black and white and only one channel - cars and TVs were a lot easier to repair then

I have disconnected it now so peace reigns, I checked all the rear lights and they still work so will just hope I don't need to tow anything.

Peter

[spider]

OK.

Oh I don't mind older engines, there's nothing really wrong with an OHV unit as far as I'm concerned (except where they refit it from longitudinal to transverse and that means it needs to come out to get the cam out, then again probably want inverting anyway) , although I know little about sidevalve units only what I remember my father saying something about having to grind to adjust the clearances, I may of misunderstood was a few years ago. I do remember seeing a much neglected Ford OHV unit where the timing chain was merrily cutting through the timing cover, much oil leakage alerted the owner to the area of concern, not to mention the noise.

I do have an old book on TV repair although I've not really had to do much to any apart from I think a replacement potentiometer a few years ago. (yes I'm aware of safety with capacitors and the CRT) , I sort of judge the CRT as a capacitor. I guess a well insulated screwdriver to the frame or suchlike with a small resistor ( ? ) will suffice for safe discharge.

On topic, if you have twin electrics ie two sockets, I'd suspect the power outlets and suchlike from the accessory socket will now not be working, I could be wrong. I don't see it affecting the main compulsory lighting ie brake / tail / indication but I guess you can simply plug it back in if needed. I'd be tempted when you next are towing to plug it in to see what happens first (the compulsory lighting section that is)

[Peter.N.]

I much prefer older engines, not so many bits to take off and much easer to work on the clutch/gearbox when they were the right way round. I think it was only the Ford side valve engine that you had to grind the valves stems on, that same engine had no water pump so you couldn't fit a heater, not that many cars had them in those days.

A lot of people complained about timing belts when they came out 'you never had to change a chain' what they fail to appreciate was that most cars were in the scrapyard at well less than 100,000 miles, bit different to now. I used to fit Perkins 4/108 engines into cars before you could buy decent diesels, these had timing gears, 100% reliable and you couldn't hear the noise because of the racket the engine made.

I was a TV engineer for 50 years, until the job ceased to exist, working on valve sets you were getting shocks all the time, we didn't take much notice of them then.

I examined the offending article and it seems to sense the voltage from the lighting circuit and switch an independent 12v supply to the trailer lights thus not loading the car circuits.

Peter

[spider]

Excellent background.

That would make sense I guess, an 'on load' sensor in effect so there's no risk to the stock vehicle wiring at all.