1nolaguy Posted March 19 Share Posted March 19 I gave been fighting with a hook up issue since last fall and it is about to have me put a for sale sign on this rv. Don't laugh you know you have been there. Long story short, after replacing all the tail light sockets and bulbs and reading all the ground lines, it appears that the issue is with the 4 pin/7 pin combo connector. I have cleaned it with electronic cleaner, worked it with a fine brush and still with issues. The tail light / brake light and signal lights on the coach, as well as the running lights, all seem to work OK. When I plug in 4 pin auxiliary lights (tow, truck light strip or magnetic base tow lights) the running lights work but nothing else. Before I replace the 4pin/7 pin combo connector is there any thing else to check? Link to comment Share on other sites More sharing options...
BradHend Posted March 19 Share Posted March 19 Did you change over to LED? Link to comment Share on other sites More sharing options...
1nolaguy Posted March 19 Author Share Posted March 19 10 minutes ago, BradHend said: Did you change over to LED? Yes. That is the two lights(magnetic), strip light, and tail lights on new toad are all led. The Original signal lights and brake lights on the rv are incandescent. Link to comment Share on other sites More sharing options...
BradHend Posted March 19 Share Posted March 19 (edited) When you upgraded the coach lights to LED, did you have to switch around the wiring to make them work? I did. Have you taken any measures with a volt meter at your trailer plug? What I’m getting at is you might have your ground/light wires backwards as a result…polarity sensitive. Re-read your reply….missed that coach was still incandescent. Have you bench tested that strip light? If it’s a cheap Amazon one, they do some weird things and some you need that special adapter for signal/brake lights. Still curious what voltage readings you get at trailer plug for brake/signal/running. Edited March 19 by BradHend Link to comment Share on other sites More sharing options...
vito.a Posted March 19 Share Posted March 19 I've had to replace the 3-2 trailer taillight converter on our coach. I used this one: https://www.amazon.com/gp/product/B0051NNUHQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Link to comment Share on other sites More sharing options...
Tom Cherry Posted March 20 Share Posted March 20 3 hours ago, 1nolaguy said: I gave been fighting with a hook up issue since last fall and it is about to have me put a for sale sign on this rv. Don't laugh you know you have been there. Long story short, after replacing all the tail light sockets and bulbs and reading all the ground lines, it appears that the issue is with the 4 pin/7 pin combo connector. I have cleaned it with electronic cleaner, worked it with a fine brush and still with issues. The tail light / brake light and signal lights on the coach, as well as the running lights, all seem to work OK. When I plug in 4 pin auxiliary lights (tow, truck light strip or magnetic base tow lights) the running lights work but nothing else. Before I replace the 4pin/7 pin combo connector is there any thing else to check? KEEP IT SIMPLE. Order a 7 pin to 4 pin adapter from Amazon. Try that. The connection point for the lights, I THINK, change. These adapters have a coiled 4 Wire flat plug. They are cheap…less than $15. Order one….try it. If it works….great…. Otherwise, you are going to have to start tracing the wires from the 7/4 pin harness back up…. Link to comment Share on other sites More sharing options...
1nolaguy Posted March 20 Author Share Posted March 20 3 hours ago, BradHend said: When you upgraded the coach lights to LED, did you have to switch around the wiring to make them work? I did. Have you taken any measures with a volt meter at your trailer plug? What I’m getting at is you might have your ground/light wires backwards as a result…polarity sensitive. Re-read your reply….missed that coach was still incandescent. Have you bench tested that strip light? If it’s a cheap Amazon one, they do some weird things and some you need that special adapter for signal/brake lights. Still curious what voltage readings you get at trailer plug for brake/signal/running. Bench tested strip (cheap o e from Amazon) and found loose ground wire at fuse. After fixing it I tested it in my truck and all worked. Not sure if this will be a fix or not, so tomorrow it's back to the rv. I want to pick up a new adapter just in case as the rv is not near anything convenient. Does anyone have experience with Hopkins Towing Solutions products? 19 minutes ago, Tom Cherry said: KEEP IT SIMPLE. Order a 7 pin to 4 pin adapter from Amazon. Try that. The connection point for the lights, I THINK, change. These adapters have a coiled 4 Wire flat plug. They are cheap…less than $15. Order one….try it. If it works….great…. Otherwise, you are going to have to start tracing the wires from the 7/4 pin harness back up…. Tom, I am having issues with both the 4 pin and 7 pin adapter. Since it is OEM from 2005 I am thinking oxidation my be playing a part. Link to comment Share on other sites More sharing options...
MyronTruex Posted March 20 Share Posted March 20 https://www.amazon.com/Oyviny-Trailer-Circuit-Indicators-Function/dp/B09C85C92J?th=1 Just found this device. Looks like it will test both 7 and 4 pin connections as well as being a 7 pin to 4 pin adaptor. What a great idea. Link to comment Share on other sites More sharing options...
Scotty Hutto Posted March 20 Share Posted March 20 I have used Hopkins as replacement parts for the 7 & 4 pin connectors on my coach with good results. That was in 2017 and all still work well (well, except when I crushed it leaving @pwhittle’s driveway — but that was my fault). Here’s what I used… https://amzn.to/43t3jFu Link to comment Share on other sites More sharing options...
Tom Cherry Posted March 20 Share Posted March 20 12 hours ago, 1nolaguy said: Bench tested strip (cheap o e from Amazon) and found loose ground wire at fuse. After fixing it I tested it in my truck and all worked. Not sure if this will be a fix or not, so tomorrow it's back to the rv. I want to pick up a new adapter just in case as the rv is not near anything convenient. Does anyone have experience with Hopkins Towing Solutions products? Tom, I am having issues with both the 4 pin and 7 pin adapter. Since it is OEM from 2005 I am thinking oxidation my be playing a part. A little confused. A loose ground, theoretically, would impact all 3 circuits. Oxidation is what I consider as corrosion in a connection. There is, memory, a multipin connector for your 7/4 Block or the rear connection. I have “fixed” many 7 and 4 and also “chassis” harnesses by cleaning. My technique is simple. There is a product or compound called NoAlox (sp?) Amazon has it. Lowes used to sell a similar one. Gardner Bender anti corrosion for Aluminum. It is the consistency of tooth paste. It has ground up aluminum fines in it. You also need a 17 caliber rifle brass cleaning brush. You put a drop or so, with a toothpick, inside each female pin orifice. Use the brush to clean. Same drill on the male pins…a small brass parts cleaning brush. Then a drop in each female and a drop or smear each male. Plug together and then unplug a few time. There IS a copper equivalent, but harder to find. Most electrical supply shops have the aluminum style. I clean my 50 Amp pins about every few years. You can also clean the contacts on the flat blades in the 7 pin. I have found issues in just about every “joint” over the years on the towing as well as the towed vehicle. A 7 - 4 “coiled” adapter has a better chance of no corrosion issues as the 7 is covered. You CAN spray with contact cleaner, but the abrasive cleaning technique works best.. Link to comment Share on other sites More sharing options...
1nolaguy Posted March 20 Author Share Posted March 20 1 hour ago, Scotty Hutto said: I have used Hopkins as replacement parts for the 7 & 4 pin connectors on my coach with good results. That was in 2017 and all still work well (well, except when I crushed it leaving @pwhittle’s driveway — but that was my fault). Here’s what I used… https://amzn.to/43t3jFu Thanks Scotty, that is the same one I was looking at. Link to comment Share on other sites More sharing options...
Tom Cherry Posted March 20 Share Posted March 20 4 minutes ago, 1nolaguy said: Thanks Scotty, that is the same one I was looking at. If you use a VOM and don’t have power there, a new one will not work…..if the trailer plug is not damaged, then contact cleaner and the anti corrosion cleaner should make it work….otherwise, there is a problem up stream…..as in the chassis harness that feeds the entire plug… Trouble shoot and isolate and then fix…. Link to comment Share on other sites More sharing options...
1nolaguy Posted March 20 Author Share Posted March 20 56 minutes ago, Tom Cherry said: A little confused. A loose ground, theoretically, would impact all 3 circuits. Oxidation is what I consider as corrosion in a connection. There is, memory, a multipin connector for your 7/4 Block or the rear connection. I have “fixed” many 7 and 4 and also “chassis” harnesses by cleaning. My technique is simple. There is a product or compound called NoAlox (sp?) Amazon has it. Lowes used to sell a similar one. Gardner Bender anti corrosion for Aluminum. It is the consistency of tooth paste. It has ground up aluminum fines in it. You also need a 17 caliber rifle brass cleaning brush. You put a drop or so, with a toothpick, inside each female pin orifice. Use the brush to clean. Same drill on the male pins…a small brass parts cleaning brush. Then a drop in each female and a drop or smear each male. Plug together and then unplug a few time. There IS a copper equivalent, but harder to find. Most electrical supply shops have the aluminum style. I clean my 50 Amp pins about every few years. You can also clean the contacts on the flat blades in the 7 pin. I have found issues in just about every “joint” over the years on the towing as well as the towed vehicle. A 7 - 4 “coiled” adapter has a better chance of no corrosion issues as the 7 is covered. You CAN spray with contact cleaner, but the abrasive cleaning technique works best.. Tom, sorry for the confusion. The RV has a double adapter similar to the one linked by Scotty above. Although these have coverings on the connector side and I have sprayed them, I have found no clear way to sand or abraid the inside of the tubes on the female connection. I will try today to pull the existing adapter and clean all connection (those coming in and those going out. I will use NoAlox (have some) before replacing wires. If that does not work I will replace adapter unit. Link to comment Share on other sites More sharing options...
Tom Cherry Posted March 20 Share Posted March 20 1 hour ago, 1nolaguy said: Tom, sorry for the confusion. The RV has a double adapter similar to the one linked by Scotty above. Although these have coverings on the connector side and I have sprayed them, I have found no clear way to sand or abraid the inside of the tubes on the female connection. I will try today to pull the existing adapter and clean all connection (those coming in and those going out. I will use NoAlox (have some) before replacing wires. If that does not work I will replace adapter unit. The 17 caliber brush will work to clean the small female connectors. Lowes or others sell small parts cleaning brushes that are brass. You don’t need a massive amount of the anti corrosion….sort of like brushing your teeth. Back to basics…. Use your VOM. Here is the diagram. Check the 7 pin first…if it don’t work there….it ain’t gonna with a new one. See the picture First….establish that the ground is good….use the OHMS or continuity….If OK….proceed…..if not….the run the tests using the ground you used on the chassis….just scrape off a little paint on the hitch… Have someone, switch ON, step on brakes or put a weight or board on brake pedal. SOME VOM’s will not work on a flasher signal…where a test light will. With the brake pedal depressed ….you should have 12 VDC between Ground and Pins 5 and 6….odds are if you do…and had a test light, you could test with a light and verify left and right. Then check tail on pin 3. The larger lugs in the 7 pin are easier to “stab” or get a good connection. Once you know there is a 12 VDC, then, if you can’t clean the 4 pin….you can use a coiled wire 7/4….that is more positive as you have a larger contact surface on the 7 pin flat lugs And you don’t leave the 4 wire flat out in the weather all the times. Just my take and experience….Good Luck. We HAVE had folks install new receptacles and find out….OPPS…issue was upstream in a harness connection… Link to comment Share on other sites More sharing options...
1nolaguy Posted March 20 Author Share Posted March 20 UPDATE: OK been working g on this since noon. I checked the strip on another truck with 4 pin an it worked fine. Using a VOM set for continuity I first checked all the wires from the strip to the end of the 4pin plug. The electrical whip on the strip was to short so I used a matching (color code) extension and hardwired them together using a solder joint and covering with shrink wrap. I pulled the 4/7 adapter (discovered OEM was Hopkins also) and checked continuity of 4pin to 7 pin and also from connection where wip from adapter connects to wire harness leading up front. All good. While apart I cleaned all connections with electronic cleaner and treated with NALOX. Put it all back together. Everything works on coach. Everything works on strip except left turn signal. At this point I am thinking it must be a bad connection where the 4 pin plug goes into the 4 pin socket. The fit is very easy so maybe it is worn? Link to comment Share on other sites More sharing options...
1nolaguy Posted April 3 Author Share Posted April 3 UPDATE: Well, I replaced the old 4/7 pin connector and all worked and then it did not. I purchased the tester linked by Myron Truex above and it showed the new 4/7 pin adapter to be installed correctly. I hired a local mobile tech to double check the wiring and lights and all were determined by him to be correct. At this point we checked all the lights twice and the seemed to work properly. We hooked up and towed about 20 miles. Stopped to check and discovered the front right wheel hub on fire (presumably unrelated to the light issue). The coach is now back in storage. The toad is at the dealers with the brake system being rebuilt, and we have decided to make this trip via car and staying in hotels. I am beginning to think this is Providence telling us to not travel or give up RV'ing. That decision is still to be made. With two significant negative towing incidence( first the hub sheered off our dolly when dolly towing and now the fire) in the last two years my wife says towing anything, at least for now , is off the table. Such is life. Link to comment Share on other sites More sharing options...
Ivan K Posted April 3 Share Posted April 3 Don't give up, the last scary incident wasn't even related to motorhoming, would happen regardless. At least you did not need Uber to get back home! Link to comment Share on other sites More sharing options...
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