Cigarette lighter only giving 0.4v??!

Cigarette lighter only giving 0.4v??!

Author
Discussion

Shaunk91

Original Poster:

7 posts

39 months

Monday 1st February 2021
quotequote all


Help needed!
Connected new cigarette lighter up and didn't work. The connections are putting out 0.4v ???? Fuse is fine obviously.

Was putting out 12v yesterday, haven't touched anything now its 0.4v

Am i missing something and being an idiot?

Helpp!!!!

paintman

7,692 posts

191 months

Monday 1st February 2021
quotequote all
Assuming your battery is good?

How did you fit the lighter's wires?


Chris32345

2,086 posts

63 months

Monday 1st February 2021
quotequote all
Make sure you connections are good and check the voltage at the fuse the supply's the power socket

Shaunk91

Original Poster:

7 posts

39 months

Monday 1st February 2021
quotequote all
Car was running when testing with a tester.

Its not getting enough power for some reason

But was putting out 12v at the connections last night

Just a standard one like this

E-bmw

9,238 posts

153 months

Monday 1st February 2021
quotequote all
You are going to have to get a multi-meter out & test back if the fuse is OK but it is basically getting nothing.

You say the fuse is OK, but is there 12v at the fuse?

You say you are getting basically nothing at the lighter, how are you actually testing it?

Have you checked the fuse since testing it, as it is really easy to short them out when testing?

If there is 12v at the fuse, the fuse is OK but there is basically nothing at the lighter, there is either a high resistance joint in between or a cable break.

smokey mow

915 posts

201 months

Monday 1st February 2021
quotequote all
Shaunk91 said:
Car was running when testing with a tester.

Its not getting enough power for some reason

But was putting out 12v at the connections last night

Just a standard one like this
Did you connect your car wiring to the two short wires in that picture of to the two spade terminals on the bottom of the main body?

Shaunk91

Original Poster:

7 posts

39 months

Monday 1st February 2021
quotequote all
Need to check volts at the fuse box then.

The wires are just for illumination.

I have a 2008 mondeo mk4
3 spade connection on car

Connected it to the spades as normal and grounded black wire to ground on spade connection.

The issue is on the car wiring to the fuse box though, those cables (that plug into the cigarette lighter spades aren't getting enough juice)

Shaunk91

Original Poster:

7 posts

39 months

Tuesday 2nd February 2021
quotequote all
Under 1v still at the fuseboard.

After driving for 30mims the spade connectors were putting out 13v. Then when i stopped the car it goes straight down again.

Ran it again (at a stand still) and they just stayed at 0.4v again.


E-bmw

9,238 posts

153 months

Tuesday 2nd February 2021
quotequote all
Like you have been already told, you need to get your multimeter out & trace it through, it is either wiring or bad connection based on everything you have said.

Miserablegit

4,021 posts

110 months

Wednesday 3rd February 2021
quotequote all
Have you mixed up the illumination feed and the socket feed? Power to the socket when you are driving around (if your car has automatic lighting you'll get 12v then).
It might be a switched supply - a lot of cars only feed 12v to the 12v sockets when the ignition is on.


ReturnedForPrivacy

4 posts

40 months

Wednesday 3rd February 2021
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Turn your headlights on, and see if you have 12V then.

My guess would be power illuminated and main power mixed up.

Shaunk91

Original Poster:

7 posts

39 months

Wednesday 3rd February 2021
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I will try the light thing but dont think its that.

Was working for a bit when 1st had the car, all i have done is disconnect the 3 spade connectors from the lighter.

Dash illumination works fine.

Like i said, was working ok for a bit when i 1st got the car. Dont really want to take apart the whole dash to trace wires.

Would it be anything to do with the alternator? Noticed my interior light flickering yesterday.

If so.. anyone know how to test a "smart alternator" (2008 mondeo)

As far as i am aware these only charge system when they need to, would it still be same way of testing with a multimeter

spikeyhead

17,337 posts

198 months

Wednesday 3rd February 2021
quotequote all
turn you headlights on. If they come on, then there's 12V available.

Then it's just a matter of working out where you're losing it between the battery and the lighter. Does it go via a relay? if not then you've probably got wiring fault.

Shaunk91

Original Poster:

7 posts

39 months

Wednesday 3rd February 2021
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Relay for lights or cigarette lighter?

Unsure if there will be a relay for cigarette lighter circuit

GreenV8S

30,208 posts

285 months

Wednesday 3rd February 2021
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Shaunk91 said:
The connections are putting out 0.4v
Measuring what relative to what?

You should have one wire close to the vehicle ground voltage and the other close to battery positive voltage. If you don't get that, your actual voltage readings will guide you to the problem.

Shaunk91

Original Poster:

7 posts

39 months

Wednesday 3rd February 2021
quotequote all
GreenV8S said:
Measuring what relative to what?

You should have one wire close to the vehicle ground voltage and the other close to battery positive voltage. If you don't get that, your actual voltage readings will guide you to the problem.
Sorry can you explain that a bit more?
(New to electrics)