Need Help on Electrical Issues
 

I need some help on some electrical issues on am having on 821. I had all of the lights working on my car and was troubleshooting a tachometer issue. The tach issue turned out to be a plug pin pushed back into the plug so that it was no longer making contact. I fixed it then went to recheck all my lights again to be sure everything else was still working only to discover that now the brake lights, the front and rear right signal lights and the left rear signal light no longer work. I have checked (visually and with a DVM) all of the plug pin connectors for pins not contacting; I have verified that the brake light switch is working. The tail lights do work when I switch on the night time running lights. The only single item that I can think of that would cause all of these lights to stop working would be the steering column mounted relay board. A picture of the board is attached. The fuses on the back of the board are good. I suppose I could have multiple failures but after all the inspection of the wiring and troubleshooting I have done I can’t imagine what they would be. I am about to push the panic button as I have a state VIN and safety inspection scheduled in about 10 days. Am I missing something here? Am I off base on thinking the relay board has failed? Any guidance troubleshooting would be greatly appreciated.

Thanks.
BD

Bench testing that little baby is quite difficult, as it has to be under load. First confirm that the bulbs on all four corners are not burned out on either of the filaments in the bulbs and that they are making a good connection. You do this by manually feeding 12v+, using a needle on each feed wire, to test each filament to visually confirm that the lights come on with both of the filaments. Once you know all filaments illuminate properly, you then work your way backwards to the trailer relay.

Looking at your post it mentioned the ONLY light still functioning is the LEFT Front?

"I fixed it then went to recheck all my lights again to be sure everything else was still working only to discover that now the brake lights, the front and rear right signal lights and the left rear signal light no longer work
"

The 3-2 converter box appears to be a Buyer Products or Curt Mfg unit.
About $15-$25 most anywhere. Advance Autoparts, U-haul etc...
https://www.buyersproducts.com/produ...iteria=5423203
https://www.amazon.com/BUYERS-PRODUC...gateway&sr=8-1
https://www.delcity.net/curt?id=Towi...CABEgJ6M_D_BwE

Looking at the ERA wiring diagram page 15 the Pick-off for the front Turn and Parking lights occurs Before the Converter.
http://www.erareplicas.com/427man/wiring/wprimer.pdf

You didn't just convert to Led bulbs per chance? That can create the same scenario you are experiencing.

That sounds very similar to the lighting problem I encountered when I was sorting out my car. I spent a week or two on testing and trying different trailer wiring units and so forth. And then I embarrassingly found it was all caused simply by a disconnected front parking light lead that just needed to be plugged back together. Might double check all the lighting connections.

My thread on subject.

http://www.clubcobra.com/forums/era-...ems-782-a.html

http://www.clubcobra.com/forums/era-...n-signals.html

Long and lot of drama/testing to simply find a disconnected light

Yes, only the left front turn signal light is still working. No sir, I did not convert to LED bulbs.

From the other posts to this question it looks like I need to check the functionality of all four bulbs by feeding 12v to each filament. I will do this tomorrow and get back to you all. I will give Bob Putnam a call tomorrow too.

By the way, in the event that I do need to replace the 3-2 converter box, how is it removed from its mounting plate?
BD

I can't remember how it's secured. It will be later today but I'll dig out my old one and see if I can refresh my memory on how they did it. Maybe double sided tape.

The front signal lights are not effected by the trailer relay: They are just part of the input for the rear but there is no reverse feedback.

Coincidentally it was my right front parking light I found unplugged and it caused all sorts of mal-functions, although I'm not sure as many as you are reporting. The trailer relay was not an issue on mine. ERA used a white foam tape - sticky both sides to fasten the relay to the bracket. I went back using adhesive backed Velcro.

That's a great idea. I'll check out the feasibility of changing my design. The only thing I'll have to check is whether the adhesive is heat-stable enough.

Bob Putnam has been helping me troubleshoot this problem. I think we are both struggling to figure out what is wrong. I thought I would run this by the ERA community on Club Cobra for ideas.
I have made the following checks –
1. Jumped 12v to each parking/signal/brake light element to verify operation – all okay.
2. Verified that each light was grounded properly at all four corners of the car.
3. Verified that all the fuses are good.
4. Verified that with the parking lights on the left and right side were equal brightness side to side.
5. Swapped the B/W and B/G wires at the ERA steering column turn signal switch, the lighting problem did not change sides.
6. Using a test light with a pointed probe I penetrated the wire insulation on the 3-to-2 wire relay to check for voltage on the wires –
a. Brake on
i. trailer side yellow – 12vdc
ii. trailer side green – 0vdc
iii. car side red – 12vdc
iv. car side green – 0vdc
v. car side yellow – 0vdc
b. Right turn selected
i. trailer side yellow – 0vdc
ii. trailer side green – 0vdc
iii. car side red – 0vdc
iv. car side green – 0vdc
v. car side yellow – 0vdc
c. Left turn selected
i. trailer side yellow – 0vdc
ii. trailer side green – 0vdc
iii. car side red – 0vdc
iv. car side green – 0vdc
v. car side yellow – 12vdc
Based on the checks above we decided that the trailer relay may be bad. I received the trailer relay assembly from ERA yesterday and tried it today. I still have problems. The left brake light works, the right brake light doesn’t work. The right rear turn signal light works, the right front signal doesn’t work. The left rear signal light doesn’t work and the left front signal light does work. I made the above voltage checks at the new 3-to-2 wire relay with these results –
a. Brake on
i. trailer side yellow – 12vdc
ii. trailer side green – 0vdc
iii. car side red – 12vdc
iv. car side green – 0vdc
v. car side yellow – 0vdc
b. Right turn selected
i. trailer side yellow – 0vdc
ii. trailer side green – 12vdc
iii. car side red – 0vdc
iv. car side green – 12vdc
v. car side yellow – 0vdc
c. Left turn selected
i. trailer side yellow – 0vdc
ii. trailer side green – 0vdc
iii. car side red – 0vdc
iv. car side green – 0vdc
v. car side yellow – 12vdc
This seems to indicate to me anyway that this new trailer relay isn’t working either. It is hard for me to believe that two relays in a row are bad.
Does anybody have any other ideas or suggestions?
BD

Damn, that is ridiculously complicated.:eek: If you pull apart the 12 wire plug that connects the trailer/flasher contraption that we use, and then, with the plug completely apart, feed 12v+ to each of the eight hot feed wires that go to each corner bulb, can you get each corner bulb to light each of the two filaments (eight separate filaments in total)?

Patrickt -
You gave me a slap up side the head! Apparently that is what I needed. I started jumping 12vdc to each of the plug pins as you suggested. I got to the right front park/sig light and it didn't work when I jumped 12vdc to it. I was applying the 12vdc to the pin in plug #7. I looked further downstream and discovered a pin on #27 plug pushed back so that it wasn't making contact. With it pushed in properly every light on the car is working now. I guess I was making it too complicated. I will recheck it in the morning as I still can't believe it. Maybe I am in a dream right now.
THANKS!
BD

Congratulations Brian! Hoping your luck is a good omen for me!

Well done. Although your short to the front parking light was in a different location than mine was (at the light) pretty close to the same issues. I also found a pin in one of my connectors not entirely engaged at one point and two wires switched in one of the big plugs during sorting out. Not blaming ERA as anything hand built is to be expected to have a random issue now and then. But from a lessons learned standpoint, especially if assembling your own car it is worthwhile to go through the entire wiring harness first and check the engagement of each pin/receiver and the wire color positions at each plug against their wiring chart.

Well that's good. Now if we can just get ACHiPo up and running.:LOL:

I'll echo what Dan said about checking all the pins if you're assembling your own car. I was lucky to notice a wire moving when I connected one of the main wire harness connection blocks (it was backing out of the connector as I pushed the two sides together. I pushed it in and heard a click. I then checked all the other connections and found a couple more like that - can't remember the exact number at this point. Anyway, it only takes a few minutes to push on each wire in every connector before assembly to make sure they're clicked into position and can't back out.

Kevin