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1973 R75/5 - electrical issues?
1973 R75/5 - electrical issues?
I've been working on a light restoration of my 1973 R75/5 that I purchased in April. I put the battery in today and got it connected and secured. But, something is wrong. With the key in - I have lights - low and high beam. But, that's it. No turn signals, no horn and I can't get the starter to roll the engine. I did change all the plug wires when it was apart, but I'm sure I have the plug wires on correctly. The ground is on and secure, and there are two contacts on the positive side of the battery that are also secure. Thoughts?
I'm stumped.
--My wife
- schrader7032
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Re: 1973 R75/5 - electrical issues?
Beyond that, I'd be looking at the starter relay for potential corrosion on the terminals.
Curious...what are the two contacts you mention on the positive side of the battery?
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
Re: 1973 R75/5 - electrical issues?
I do wonder if it's the switches though. I'm going to replace both. We'll see if that helps.
--My wife
- srankin
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Re: 1973 R75/5 - electrical issues?
Re: 1973 R75/5 - electrical issues?
--My wife
- Darryl.Richman
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Re: 1973 R75/5 - electrical issues?
If I understand right, that you have lights, but no start, then it looks to me like the switch the "nail" pushes on is not making contact to allow power to the rest of the system. Look at the 30/51 (power) terminal on the circuit board and the switch between that and 31 (ground). If the key doesn't make that switch actually contact 30/51, then there's no power to the horn or the starter button.
(I snipped the wiring diagram from the /5 workshop manual in the BMW Models info in the website's Knowledge Base.)
- cbclemmens
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Re: 1973 R75/5 - electrical issues?
I would start with the ignition switch. It sounds as though power is not getting to pins 15 and 30. You might just need to clean it.
Craig
Re: 1973 R75/5 - electrical issues?
--My wife