Is my solendoid faulty?

[rodrayner]

Hi, I think my ( brand new ) solenoid may be faulty but just need conformation before i return it to be replaced.

My battery is fully charged showing just over 12 volts. The solenoid is a 4 pole one so i connected negative from the battery with jump leads to one of the spade connectors and positive from battery onto the other spade connector.

The solenoid clicks but when i check across the two top connectors on the solenoid i get nothing with my multi meter.

I also connected the negative on the multi meter to the negative on the battery with the jump lead still connected to one of the spade connectors on the solenoid. I then hooked up the positive from the battery to the other spade connector, the solenoid then clicks. If the check across the top connectors on the solenoid with the positive from the multi meter at best i get around 0.5 volts ?

Whats confusing me is the solenoid is clicking... but does this means its working... according to the multi meter its not but could just do with someone confirming. I bought a new one as this is just what the old one does so i'm not 100% this is the problem.... or am i just unlucky and the new one is also faulty :-(

The battery being used is quite old but it was fully charged and does read at just over 12 volts.

Thanks.

[sparkythecat]

rodrayner said:

Hi, I think my ( brand new ) solenoid may be faulty but just need conformation before i return it to be replaced.

My battery is fully charged showing just over 12 volts. The solenoid is a 4 pole one so i connected negative from the battery with jump leads to one of the spade connectors and positive from battery onto the other spade connector.

The solenoid clicks but when i check across the two top connectors on the solenoid i get nothing with my multi meter.

The solenoid is really just a big switch relay. When you apply 12v across it, you're turning on the switch to allow the large starting current to flow to the starter motor. To test if it's working, you need to measure resistance or continuity across the other two terminals, not voltage.
With no volts applied, your meter should show an open circuit across the other 2 terminals and with 12 volts applied, a continuous circuit

This is assuming that you are bench testing it and no other circuits are connected

[Sheepshanks]

As above, the solenoid looks something like this inside:



"12V in from key" is the positive and the Earth is the negative.

There's no electrical connection internally from the coil to the contacts.

I'm just slightly alarmed by what you're doing - whatever you do, don't connect the battery positive and negative directly to the contacts (12V in and out in diagram) and then energise the coil as at best something will quickly melt and at worst the battery will explode.

[rodrayner]

Hi Sparkythecat,

Thanks for the reply, makes a lot of sense.

Have switched the multi meter over to beep mode.... double checked it works by touching both contacts from the meter and i get a beep :-)

Tried the solenoid... beeps all the time... no matter if power is attached or not... i presume this means its always open and therefor faulty.

Tried the old one... nothing but it does click... cleaned up all contacts and i did managed to get a faint beep once but nothing since... so presume that one is also dead.

Just bad luck i expect... suppose i better order a new one.

Thanks

Edited by rodrayner on Saturday 19th March 14:42

[rodrayner]

Hi Sheepshanks...

No need to panic :-)... i haven't connected the battery to the top terminals only the spade connectors...

Thanks..

[Sheepshanks]

rodrayner said:

Tried the solenoid... beeps all the time... no meter if power is attached or not... i presume this means its always open and therefor faulty.

If the meter beeps for continuity (meter leads touching each other) then beeping when connected across the solenoid means the contacts are always closed - ie they've welded together or something mechanical has broken inside.

[sparkythecat]

^^^^^
Sheepy's right, its fubarred.

[rodrayner]

Thanks for your help guys.. new one ordered.

Ta

[sparkythecat]

Top lurking by the way Rod. 5 posts in over 10years is awesome.
I presume you car must be ultra-reliable, what is it?

[rodrayner]

Sparky... originally it was a TVR Cerebra... when i joined... hence why i had to join... not overly reliable... but didn't care as it was 100% fun :-).. unfortunately exchanged for a Maserati 3200 Special edition... fun but not as much as the TVR... anyway that was sold after the first service bill and now I'm Mr boring by driving around in a E Class.... the reason why i don't need to ask many car related questions either... ;-)

This post was about my lawnmower... originally posed in the garden section but moved here... maybe because i wasn't clear it was actually a lawnmower...

Cheers for the help

[Penelope Stopit]

I would move house if I were you
Have a natter with your lawn mower, it will tell you the grass is always greener on the other side