overheated trailer plug

Submitted: Wednesday, Mar 14, 2007 at 14:42
ThreadID: 43241 Views:5423 Replies:7 FollowUps:7
This Thread has been Archived
My Coromal Silhouette (2004 model) has a 7 pin large round connector. My Patrol has a 7 pin small socket. I bought a "conversion-link" from Supercheap which appeared to work well. This last weekend I blew the fuse for the Patrol's indicators twice whilst towing. On checking the Coromal's plug there were signs of a melt-down starting. Obviously heat had generated there. I have just replaced the large round plug with a new one - I used the same large round type, as it seems to allow for more amps. I'm guessing I need to replace the small socket on the Patrol with a large one (but will I need to boost the wiring too?). I have been reluctant to do that because it means converting a couple of other trailer plugs too (both boat & box-trailer use small 7 pin round connectors). Would the "conversion-link" be the cause of the over-heating or should I look elsewhere for a possible fault?
Thanks in advance :-)
Back Expand Un-Read 0 Moderator

Reply By: Sparkie C - Wednesday, Mar 14, 2007 at 15:43

Wednesday, Mar 14, 2007 at 15:43
Hi Jamas, overheating is a sign of poor connectivity , or a high resistance joint or overload. If the only problem has been a melt at the van plug it probably was caused by a poor contact (loose or dirty) in the van plug.
Was it the first time you used the van with this connection or has it been ok in the past?
Are you charging the van battery or using the plug to run the fridge as these loads will be too heavy for a trailer plug and may be causing the problem ,if so you will need to uprate the wiring.
Good luck chasing the problem.
Sparkie
AnswerID: 227409

Follow Up By: jamas - Wednesday, Mar 14, 2007 at 16:29

Wednesday, Mar 14, 2007 at 16:29
Thanks Sparkie, as far as I know I am not charging the camper's battery or running the fridge from the car. I did have the fridge on the 12v setting, but I believe that draws directly from the deep-cycle Trojan in the camper. To check whether the camper battery was drawing a charge from the car, I put a meter on the camper-battery terminals with the camper disconnected from the Patrol. The reading was 12.42 volts. This didn't change at all, even after connecting it to the Patrol and running the engine at about 1800 rpm. I'm hoping you're right about it being a dirty connection. Some mudwasp had made it's nest in the connector and I had to clean it out before we left. I also sprayed it with an "printed cicuit-board cleaner" which I think is CTC. I probably didn't do a good enbough job of cleaning it. I have used this big-to-small link before but didn't notice any overheating - but I didn't go looking for it either. I'll make sure it stays clean and keep an eye on it. Many thanks :-)
0
FollowupID: 488183

Reply By: Robnicko - Wednesday, Mar 14, 2007 at 15:43

Wednesday, Mar 14, 2007 at 15:43
Jamas,
My guess would be bad connectivity between the convertor and original plug. I run two plugs on the back of my 80 series, 1 large round seven pin and a rectangle plug. The reason I did this at the time was it cost me about 1/3 the price of one of those converter things. They also are quite bulky which over road vibrations could have worked it's way loose enough to cause bad connection (heat build up). Lucky you found out that way and not by a smouldering mess.

Rob
AnswerID: 227410

Follow Up By: jamas - Wednesday, Mar 14, 2007 at 16:33

Wednesday, Mar 14, 2007 at 16:33
Thanks Robnicko. I have thought about fitting a large socket to the Patrol and also leaving the small one in place - and may yet do this.
0
FollowupID: 488184

Reply By: Mark Taylor - Wednesday, Mar 14, 2007 at 16:21

Wednesday, Mar 14, 2007 at 16:21
As an old auto sparky.. your problem is not in the plug design.

Either you have a loose connection in the plug or else you have a short in the wiring in the blinker circuit on the van. Shorts burn or heat from the point of trouble back towards the power source.

Go find a good auto sparky and let him/her sort it out.

Cheers

Mark T
AnswerID: 227416

Follow Up By: jamas - Wednesday, Mar 14, 2007 at 16:35

Wednesday, Mar 14, 2007 at 16:35
Thanks Mark, I'm hoping it was the dirty connection and will keep a close watch on it from now on. :-)
0
FollowupID: 488186

Reply By: Member - Vincent A M (NSW) - Thursday, Mar 15, 2007 at 09:33

Thursday, Mar 15, 2007 at 09:33
as it is probably a bad connection as already stated, I tow all sorts of things for work & my patrol has 6 types of plugs on it, but i always carry a can of spray contact cleaner & often spread the pins so it is has a good connection as most people are not gentle when they wriggle the plugs apart closing the pins on the male plug.

as i tow some trailers 30' that have many clearance & tail lights by fitting LED globs has been great help (my old 94 patrol never had a problem but my 04 will blow fuse's at the slightest extra load)
AnswerID: 227610

Follow Up By: jamas - Thursday, Mar 15, 2007 at 09:55

Thursday, Mar 15, 2007 at 09:55
I hadn't thought of checking and maybe spreading the pins - thanks for that one Vincent :-)
0
FollowupID: 488348

Reply By: Keith_A (Qld) - Thursday, Mar 15, 2007 at 10:25

Thursday, Mar 15, 2007 at 10:25
Hi Jamas - agree with above - get an auto electrician to check it - stray heating can cause rather large damage. It happens while you are unaware - eg towing (and it is down the end of the fuel tank).

Could I make 2 suggestions :

1. I notice you have checked that the van is not being charged from the car. If you do want to charge from the car to the camper, which keeps the camper battery fully charged, get an anderson plug with heavy wiring from the car battery (via a fuse and solenoid - redarc or similar). As voltage drop is your biggest problem over the distance (5-6 mtrs) you need some seriously heavy cable to minimise it. Also ensure the anderson plug EARTH - either full length back to the battery, or wire to the chassis connection is of similar heavy guage.

2. Check out this web site. For all things camping electrical. Site Link
In particular, read the 'Electrics - wiring woes' article.

....................Regards.................Keith
nb owned a Coromal Magnum (loved it) - now have a Coromal Corvair (both offroad)
AnswerID: 227621

Follow Up By: jamas - Thursday, Mar 15, 2007 at 10:44

Thursday, Mar 15, 2007 at 10:44
Hi Keith, thanks for the tips. I have considered setting the trailer up for charging and I already have a couple of Anderson plugs lying around somewhere. I'll put it on this months list of things to check out thoroghly and then maybe even do it. :-)
0
FollowupID: 488360

Reply By: Dion - Thursday, Mar 15, 2007 at 13:02

Thursday, Mar 15, 2007 at 13:02
Change the plug, or change/add the correct socket to your tow vehicle.
Do away with the adaptor ("conversion link"), all the adaptor does is provide an additional point of failure.

Cheers,
dion.
AnswerID: 227641

Follow Up By: jamas - Friday, Mar 16, 2007 at 00:58

Friday, Mar 16, 2007 at 00:58
Hi Dion, I have already changed the offending plug. I will probably add a 7 pin large socket to the Patrol. Cheers mate :-)
0
FollowupID: 488527

Reply By: Keith_A (Qld) - Thursday, Mar 15, 2007 at 18:26

Thursday, Mar 15, 2007 at 18:26
Jamas - there is one thing you NEED to check.
The Campers have electric brakes.
When installing a brake controller, they fit a thick wire (normally blue) for the power to the brakes, but sometimes forget to fit a larger earth wire to the plug (on the CAR.)

The same current that flows down the power wire, must return via the earth.
If the EARTH wire is too small - the current burns it out.
Perhaps that is the cause of your burnt wire?......................Keith
AnswerID: 227686

Follow Up By: jamas - Friday, Mar 16, 2007 at 01:07

Friday, Mar 16, 2007 at 01:07
Hi Keith, I am in the process of checking the wiring. You make a good point about the electric brakes and I will check it out. Something I have remembered since starting this thread, the previous owner mentioned a switch under the dash. I can't remember what it was for and I haven't touched it - it's indicating that it's in the "on" position. I will check this out tomorrow. I am reasonably confident that it threads back to the trailer connector, but I've yet to confirm it with a meter. The only thing that makes any sense is that he used it to charge his caravan battery - but then the wiring would have to be heavier, and I'm not sure that it is ... I will continue to research it. (Before the camper, I only towed my boat and didn't have these issues! .. lol)
0
FollowupID: 488532

Sponsored Links