26 replies to this topic

[dklawson]

What year is your Mini?  If I have some time tomorrow I will look at a wiring diagram for it assuming I have a PDF copy of the appropriate one.

[fergy26]

It's 1880. Thanks that'll be grear

[dklawson]

In an earlier post you mentioned problems with the brown wires connected to the starter solenoid,  Before doing anything else, resolve that issue.  The terminals on the solenoid should not move.  They should be clean.  And of course, they should be connected correctly.  Regardless of whether you are talking about a pre-engaged starter solenoid or the earlier stand-alone type used with the inertia starer, the main battery cable connects to a threaded solenoid terminal and all the brown wires connect to that same post.  The other threaded post/terminal is "switched" and only delivers power to the starter motor when the key is in the start position.  Make sure all the connections at the solenoid are clean and tight.  Since this connection point is "hot" all the time, make sure you disconnect the earth cable in the boot before working on the solenoid connections.  You do not want to risk your wrench bridging that hot post to chassis ground.  

 

Returning to the circuit, I do not have a diagram specifically for a 1980 but one I have is marked "1979 on".  

 

In that diagram a single white wire leaves the ignition switch and powers several un-fused things such as the oil and charge warning lights along with power to the ignition coil.  More importantly, this white wire goes to the fuse box.  The "other side" of the fuse where the white wire connects powers:

The gauge voltage stabilizer,

the backup lamp,

The turn signal (NOT hazard) flasher,

When fitted... this circuit also powers brake warning lights, 

 

If anything on the "downstream" side of the fuse were causing this I would expect the fuse to blow.  Regardless, as a test, I would locate the fuse for the circuits I list above and remove that fuse, then start the engine and see what the charge warning light is doing.  If the light goes off and behaves normally your wiring has something amiss in one of those fused circuits.

 

If the light behaves the same, I would be looking for an issue either with the brown wire running from the starter solenoid to the ignition switch, the ignition switch itself, and/or the white wire from the ignition switch to the warning lights.  However, do not start here... address the wiring connections at the solenoid FIRST before any testing, including pulling the above mentioned fuse.

[KernowCooper]

I'd be interested in what the voltmeter says with the other alternator on it, 13.7-14.2v at 2000rpm

[fergy26]

dklawson- thanks for your help, ill have to wait until friday to carry out more work but ill order a new starter solonoid tonight and fit that and then follow your advice. 

 

Kernowcooper- i put my original alternator back on and it read 14.1. it would hold this until the light got very bright and then the car would start to misfire and then just die until it ticks over for a few seconds

[lrostoke]

I'm struggling see why you need a solenoid.

 

The solenoid only acts like a junction for the power wires..

 

The battery connects to one terminal and all the main power feeds including the main charge wire from alternator connect to the same terminal.

 

So even if the solenoid was broke, with engine running car would still charge and get power.

[fergy26]

Ive had problems with it before due to corrosion on the terminals which must have broke the circuit which cut the whole power to the car. I managed to clean the solonoid to ensure it was earthed through the body correctly and it solved that problem but when i was looking the other day it seems in a worse state no so a new one wont harm it

[lrostoke]

probably worth doing some basic continuity tests.

 

multimeter take a voltage reading at the alternator output.

 

take another at the solenoid connection (the one the battery cable attaches to)

 

take another at the battery

 

see if you've got continuity...if voltage drops at any point , then a bad connection upto that that point or after the last known good point

[fergy26]

ok ill give that a try when i can get time. Thanks

[fergy26]

Finally fixed! The new starter solonoid cured it. Thanks for all your help!

[Whizzbang]

On my 1967 Mk1 Cooper S I have the original dynamo and regulator and have a similar issue 

with the red ignition lamp only dimming and not fully extinguishing.

[Spider]

On my 1967 Mk1 Cooper S I have the original dynamo and regulator and have a similar issue 

with the red ignition lamp only dimming and not fully extinguishing.

 

You may wish to start a fresh topic here as the previous discussion was about Alternators. Faults and Fault finding Dynamos is quite a different kettle of fish.

 

However, I'll add that start with basics - is the fan belt tight ?