You will apreciate that I cannot see from the image, but the tester pen as you call it, looks to me very like a 100-250v tester
the sort you insert into the live conection of a socket to test the power to the socket

that ice box is 12v and if I am correct regarding the tester pen it will not help
I think you have something like this
Glow Mains Tester Screwdriver – Professional 5” (125mm) Neon Lamp Domestic Electrical Terminal Circuit Socket 240V Voltage Test Slotted Screw Driver Pen with Safety Insulated Handle and Pocket Clip : Amazon.co.uk: DIY & Tools

You need something similar to this
Silverline 633597 Circuit Tester 6V and 12V : Amazon.co.uk: DIY & Tools

 

Hello @Macboatmaster,



Hello macboatmaster,

Thank you very much for your reply. Yes was able to look at your advice and I think you are right the pen is more for mains electrics.

Sorry for delay, I am not an amazon supporter so have been looking in the local shops for a multimeter that works with lower voltages. Been to quite a few and can't find one, will have a look on ebay next.

Once I'm able to get this lower voltage multimeter, do you know which part of the internals I would use it on to check the circuit?

Side question - do most non-mains powered items for e.g. battery powered or car lighter powered items run on these lower 6-12 voltages? (Just interested).

Thank you again for your time. Hate throwing away lumps of plastic.

 

Belfastnurse

Your reponse to my advice would be appreciated

 

You do not need a multimeter to simply test if 12v is being delivered
You need what I linked to - and as you say there is no ned to buy it from amazon

To answer your other question - the fact something has a cigarette type 12v socket connection in a car does not mean it is 12v output
for instance my phone charger and my tablet charger - in car deliver 5v

If you look at one your images you will see your ice box or at least one part of it is 12v DC - direct current

Depending on cost of the ice box and age - any professional type testing, unless you can ask a favour of some possible contact is likely to cost more than it is worth

If 12v is being delivered to it - more than likely it is a circuit problem of a nature that you will not solve or even find with a tester or indeed a multimeter

 

You do not need a multimeter to simply test if 12v is being delivered
You need what I linked to - and as you say there is no ned to buy it from amazon

To answer your other question - the fact something has a cigarette type 12v socket connection in a car does not mean it is 12v output
for instance my phone charger and my tablet charger - in car deliver 5v

If you look at one your images you will see your ice box or at least one part of it is 12v DC - direct current

Depending on cost of the ice box and age - any professional type testing, unless you can ask a favour of some possible contact is likely to cost more than it is worth

If 12v is being delivered to it - more than likely it is a circuit problem of a nature that you will not solve or even find with a tester or indeed a multimeter

Thank you. So now I have the tool. Where or how do I test it? So I plug it into car and place tool... where?

 

From what I see you have a 12 V DC impeller fan (it sells on Ali Express for $18) and a couple of wires going to what I can only guess is a thermoelectric cooler from which it blows cool air into the ice chest. Either that adapter has a fuse blown in it, or it is not wired on correctly, or your 12 V car socket is not active. Other than that there's not much that can go wrong with that simple device. Note that many auto power sockets require the key to be turned on before they are active.

 

Quick question... what prompted you to change the DCV male power plug? I see those things as pretty robust. When you changed it out, did you match configuration from the old to the new?

 

If you get the polarity backwards on your thermoelectric cooler it's going to heat your ice chest rather than cool it. In fact, most of these devices market this action by having a switch on them that you can throw to either cool your beer can or keep your hot coffee hot.

 

By the wiring colors, it looks like the power cord is an EU AC cord where brown is live and blue neutral, whereas the internal wiring is red positive and black ground DC wiring. The way it's wired, the blue wire in the cord is going to be the positive wire.