I've recently acquired an oil pressure gauge and an ammeter to fit to my 1968 1000 saloon, the oil pressure gauge I'm ok with but I have little idea of how to wire in the ammeter, I dont want to blow up the electrics. I would appreciate a kind of idiots guide on where I wire it into.
Many thanks
Tony R member No 55292
Welcome to the forum! First thing to realise is that the ammeter wiring is completely unfused, and has the capability to start a fire if it shorts out! So you must use heavy cable - and you must make sure it can't chaff against any metal parts - and is very well grommeted where it passes through bulkheads. First disconnect the battery - then look at the start solenoid and see the brown cable. You need to take that cable off - extend it to the ammeter, bring another cable back from the ammeter and connect it where the brown cable was originally connected. Reconnect battery and start up - obviously you hope to see a charge registering on the meter when you rev up. If there is a discharge showing - disconnect battery again, then swap over the connections on the meter and try again. Simples!!
Great! So its brown cable from solenoid to ammeter, another cable from ammeter to 'A' connector on control box. Many thanks for your speedy reply and I'll be fitting it tomorrow weather permitting.
Hi all
Wired in the ammeter as directed and alls well.....I think. With the engine running the meter reads ' 0' or just a tad in the plus side. when the side lights are on it shows -5 and with headlamps -10.
I take it the ammeter is working, but are these readings ok or should there be more of a plus reading from the dynamo. In effect I dont know whether its telling me 'alls well' or whether there's not enough charge going to the battery.
I did have a problem with the battery running down quickly, but put it down to the fan belt which was a bit slack, but this was the main reason for fitting the ammeter so that I could have a visual reference.
The benefit of your experience would be greatly appreciated.
When you rev up - the charge should be slightly + , even with all the lights+ heater +wipers on! I think you have just found why the battery goes flat. Try tightening the fan belt - although if it has been running slack - it really would be better to fit a new one. Tightened up slack belts often snap soon after........
Yes, thanks for that. The readings I have described are with a new fan belt fitted and I get the negative readings with the lights on and engine running, I haven't tried it with heater and wipers as well...... The dynamo was fitted new 8 or 9 months ago together with a new wiring loom and the car has done less than 200 miles in that time, so I wouldn't expect a fault there, but I'm a bit of a novice so could well be wrong. I got the ammeter from ebay, is used, and calibrated 30+30-. Could the meter be dodgy perhaps?
Is the wiring the correct way round as BMc says you should be staying in the + most of the time. You could ask an Autoelectrician to check the ammeter is functioning they may have a calibrated unit that can tell you right away if you have got the wiring the wrong way round.
Assuming the ammeter, dynamo and battery are working fine then you may need to check out the charging circuit in more detail.
Easy to check if right way round - just switch on the lights - is it reading a discharge ? If it's not charging with lights etc on - it's either a knackered dynamo (but you say it's new) or the control box is needing to be adjusted. Section N9, page N11 of the Workshop Manual.
The control box may be a possibility as its a replacement that was fitted recently when the original was found to be faulty and not allowing a charge at all (red ignition light permanently on and battery running flat).
The replacement was supplied and fitted by a friend of a friend, it cured the ignition light problem, but as you suggest may need adjustment .
Your comments and advice are very much appreciated and I think checking the control box is the next job
Message received and very useful. Once again many thanks. There's a little jobbing garage in the village who are friendly and helpful, so I think I'll run the car to them and ask them to check the control box, I'm not too confident with doing any adjustment of this nature myself.
Hi all
Thanks for all your replies. The problem was the control box, fitted a new one and all readings are as described above and charging ok. Incidently can the old control boxes be reconditioned ? It seems a shame to bin the old one if it can be reused
I've been interested in reading this. I wired one into my old 1098 exactly as described, using the handy connection on the solenoid. In an older car......where the solenoid is different and lives high up on the bulkhead......what would be the best way to proceed? Bearing in mind that this type of solenoid does not have the aforementioned spade connector.
I would appreciate a kind of idiots guide on where I wire it into. 
