Wiring questions

alang · Post by **alang** » Sun Mar 15, 2009 12:10 pm

Simple question... should I have a Control Box, because I can't find one (as per fig 18 of the manual)

If yes, where should it be

My '59 Dexta came with an alternator fitted and I wondered if this makes a difference.

I would like to fuse some 12V feeds but am unsure which to fuse and what rating is required - e.g. the feed to the Heater Switch. Is there a newer 'alternator' circuit diagram I could take a look at

I seem to be able to wire and feed everything OK. The lights all work. I fitted a heater switch to compliment a new fuel primer OK - both were originally missing. The new main/light switch seems OK but I notice the key does not prevent starting and would appreciate knowing what isolation switches are recommended (with public showing in mind).

Problem with the oil pressure switch - the switch stays open circuit when the engine is off

Is there a fix

Couple of things I have noticed whilst doing the work.
1: Putting back the original heater plug was difficult as there is a pipe exiting the block right behind it. I think the heater has gone in crossed - but tight.
2: Getting the oil pressure switch out requires either a very short spanner, strong hands and steel knuckles or some sort of special spanner. I hope the new one can be socketed in.

Any help will be appreciated.
Alan

aldo · Post by **aldo** » Mon Mar 16, 2009 9:31 am

Hi there Alan
the control box is the voltage regulator for the old generator - its usually behind your dashboard. Older alternators had a similar regulator setup. Most alternators these days have the regulator built in, which is what you've probably got, so no need for a separate regulator, and that's why you cant find one.

If you want to fuse the heater switch (or any high current draw) then usual practice is to fuse the battery feed wire as close to the battery as possible -that way the fuse blows before any wires get warm. You will need to find out how much current the heater plug draws, so that you can pick the right size fuse. So for example, maybe the heater plug is 15 amp/12volts (that's just a guess) - so you would pick a fuse at say 20-25 amp/12volts, and the wire you use to supply the heater plug should be rated at least 30 amps. Just remember that the fuse is there to protect the wiring, not the heater plug or headlamp, or whatever you are wiring up.

alang · Post by **alang** » Mon Mar 16, 2009 3:42 pm

Hi Aldo,
Thanks, that's the answer I was hoping for.
I'll try and get a suitable fuse holder and isolation switch to fit just after the + terminal of the battery.
Having read your answer I can see there are two holes below the proofmeter and room behind for a control box.
It would be interesting to poll what percentage of Dexta's have been converted to use an alternator. My guess would be that most concourse condition Dexta's would be 100% dynamo and that > 50% of "working" Dexta's would have been converted.
Cheers
Alan

Dunggatherer · Post by **Dunggatherer** » Mon Mar 16, 2009 3:45 pm

The oilpressure switch is of the non-fixable type.
The only remedy is to replace it.
The good thing is they're only a few pounds/euro's/dollars.
I found there are two sizes of thread,but some have an adapter.

I invested in a set of short spanners,very cheap,since you won't be applying much force anyway.
The size of the hex is 24mm, or 15/16 inch,but an inch will do just fine.
A socket will not do,once you are done mounting the switch,there's no room to remove the socket.

Good luck!
Rob.

alang · Post by **alang** » Mon Mar 16, 2009 5:21 pm

Hi Rob,
Thanks, I have just ordered one.
The old switch had probably been there since July 1959 and getting it out required a specially bent spanner in combination with mole grips.
But it sounds like the new one wants to be firm but not strangled - I'm an over tightener.
Cheers
Alan