12v dc

[jimmydj]

owner tc250

need help on 2 12v dc plugs.

after rewiring 120v system from factory with help from this forum.
(advised from forum factory had reversed wires, turned out true)
1st time decided to plug in cell phone charger and no power.

one plug at helm and one at port seat area.

thanking all in advance
jim

[Sea Wolf]

Jimmy-

Since no one else has stepped up on this, I'll give it a try.

What follows is a set of tests to determine where the problem lies. You may not have to do some of them, depending on what you already know.

1. Are you sure the phone adapter/charger is working? Does it work in another vehicle? Also, there's a fuse built into the cigarette lighter adapter/plug in most units. It could be blown. Unscrew the plug body halves and have a look!

2. Will another 12 v appliance with the same plug work in the outlet? Maybe it is hot! Or maybe you have a plug contact problem?

3. Is the power turned on in the boat? Battery switch on? Other 12v circuits live and working? The phone adaptor is probably polarity sensitive and won't work with reversed polarity. Do other electronic devices like radios, depth finders, etc. work?

4. Are the 12 v plug outlets turned on/off by a circuit breaker on the panel? Does the circuit breaker's light come on? Is there an additional fuse in line after the circuit breaker? The female adaptor plug receptabale usually comes with an in-line fuse from the manufacturer. Follow the supply hot wire back from the adaptor to the origin or circuit breaker, looking for a "maverick" fuse.

5. Is the female adaptor plug receptable properly grounded? Check for a ground wire attached to the metal cylinder on the outside of the receptacle. Follow the ground wire back to a group of ground wires on a common connector (called a "bus"). If you can't find a ground wire, make a temporary one up and then plug the phone adaptor or something similar into the adaptor and see if adding the ground makes the difference. Your phone adaptor needs both wires or halves of the circuit to work.

6. Do you have a test probe light or VOM meter? What we need to do now is test for power using a probe of some type. Go back to where the hot wire for the 12 v adaptor circuit first originates from the other hot leads behind the helm. Start by testing to see if the lead is hot by connecting the hot lead to the ground through your test probe or VOM meter. Next, repeat the process, working towards the adaptor outlet at each connection in the hot wire lead to see where the voltage is lost. You may have a bad connection or broken wire somewhere.

By this time, you will have checked out most of the possibilities. If you still haven't found the problem, let us know and we'll see what else we can think of!

Good Luck!

Joe.

[thataway]

Joe, as always, gives an excellent review of how to trouble shoot the problem. I assume that you have the digital volt meter. I would go to the local radio shack and buy a 12 volt cig plug. Put two pig tails on it and mark these "+" and "-". Plug this into the adaptors and check the voltage and polarity (you can do the same thing on the lug on the back of hte plug, but it is harder--and occasionally I had seen defective cig lighter sockets. Another possibility is that for some reason the cell phone adaptor is not making full contact to the bottom of the cig ligher socket. Sometimes these are hard to push in all of the way. As I recollect the cig lighter on the dash fuse is on the back pannel. It may also have a breaker on the side below the shifters. (Sorry I am not near the boat to look).

[Grumpy]

Just a silly though from personal experience. There are TWO kinds of DC adaptors out there. One runs downriggers and the other runs automotive type plugs and they do not posess compatible reproductive abilities !!

Merv

[oldgrowth]

Jim – If you don’t have your problem solved from the above posts (which are all good), there are two other things to look for.

1. Some male cigarette type adapters have ground (negative) strips on the side (sometimes only two) and the female receptacle has just a couple of ground (negative) strips on the inside. If the two are not lined up properly (not making contact) you get no current.

2. Some male plugs “tit” that sticks out on the end is too short to make contact with many female receptacles' positive connection. Check the length of the tit on the male plug. If it is less than a quarter inch in length, it can be the problem on some female receptacles.
_________
Dave

[jimmydj]

thanks again for the tips.

i have plugged in the truck a 12 volt coffee maker and it works there.

not on the tc.

cell phone charger same.

2 others also.

was advised from dealer there is some switch in battery box that may be problem.

will check that out soon.

thanks
jim

[iggy]

I won't go into a long discussion about 'tits' on 'male' connectors, other than to suggest that Dave might want to go back and look at his high school biology text book for a refresher course . . .

Some of these have been mentioned before, but here are a few more tidbits:

(A) IMHO, a digital voltmeter is an absolute necessity, on the boat, or around the house. If you don't know how to use it properly, you definitely want to learn how! e.g. (i) VOLTAGE: you (carefully!) measure voltage on live circuits; current does not flow through the meter during this measurement, but you want to be very careful about touching any live wires. A 12V battery grounded (through jewelry, for example) can lead to severe injuries. 120V can obviously cause fatal electrocution. (ii) Resistance - is NEVER measured on live circuits. Good connections should have very low (virtually zero) resistance. Poor connections (e.g. corrosion) have high resistance and can cause heat buildup and signficant voltage drops. (iii) CURRENT#1 (amps) For current measurements, the circuit must be opened and run through the meter. (Large currents will immediately fry small wires, and low current voltmeters!) CURRENT #2. Current probes are available that clamp around a closed wire and magically measure the current through the insulation, with no direct contact. These probes may require some knowledge when used on AC vs DC current.

Lighter receptacles can be notoriously unreliable! Sometimes the socket works with most plugs, but an occasional plug does not make good contact. Sometimes the internal spring on the plug ('tit'?) is too strong and the plug gradually works loose. Likewise, some plugs work with most sockets, but just don't seem to work in a new situation.

FUSES: Adapters sometimes have visible fuses wired in series with one of the connecting wires. However, many cigarette lighter plugs have internal fuses that are easily overlooked. Unscrew the ring, remove the 'tit', and you'll often find a fuse in there.

OBSOLETE CONNECTORS: The whole technology of cigarette lighter connectors has long since been obsolete (or should have been). With fewer and fewer of these sockets actually being used to light cigarettes, does anyone know why we still use these bulky and unreliable connectors? I've been waiting for years for the standard to change to a small, lightweight, polarized socket and plug. It is getting to be a real pain traveling with a 12-V cell phone charger (and large plug), a 12-V GPS charger (and large plug), a digital camera 12-V charger (and large plug), an NiMH charger (and large plug), and then of course, a three-headed octopus that allows me to use three of these chargers at once. Wouldn't something similar to (but NOT interchangeable with!) an 1/8th-inch headphone jack be nice?

Good luck with the gremlins!

ejg