Electrical Problems

[neilsjuke]

I use a fibreglass pencil or a brass one with Switch cleaner lots on eBay

http://in.rsdelivers.com/product/rs/pro ... 14868.aspx

Super 10 Switch Cleaning Lubricant
Switch and contact cleaning lubricant. Quickly removes tarnish and other deposits. Residual lubrication film protects contact surfaces. Prevents arcing between dry contacts. Safe to use on plastics, rubber and other delicate materials.

Neil

[Galwaylotus]

My steering Universal joint has a wire from a column bolt to a rack bolt to be sure that the column is earthed, because the U/J is rubber.

I seem to remember.

I made a jumper with ring ends crimped on and installed one end under each washer and nut across the U-joint. I then filed a little paint from the steering rack housing and made another jumper from the rack to the earth bobbin. I captured one end terminal under a hose clamp and tightened it securely to the rack and now the horn works! Thanks for the advice.

[billwill]

My steering Universal joint has a wire from a column bolt to a rack bolt to be sure that the column is earthed, because the U/J is rubber.

I seem to remember.

I made a jumper with ring ends crimped on and installed one end under each washer and nut across the U-joint. I then filed a little paint from the steering rack housing and made another jumper from the rack to the earth bobbin. I captured one end terminal under a hose clamp and tightened it securely to the rack and now the horn works! Thanks for the advice.

Aye, that's pretty much what I did.

Make sure it doesn't catch on the fibreglass bodywork in the vicinity. And be sure to test it from full lock left to full lock right on the steering.

[Galwaylotus]

Rather than start a new thread, I dedided to add to this one.
I drove to work last week (25 miles) and home that evening with no issues. I had a meeting that night about a mile and a half away and it was light when I started. After the meeting, I took my normal two or three tries to start the engine then up with the light pods and on with the headlamps. Must admit they weren't too bright. I saw the charge light glowing dimly but couldn't get it to go off. When I got home I parked the car and shut off everything. Next morning, the engione would only crank slowly and wouldn't start!
I pulled the battery that evening and gave it a good charge. It seems ok now but I wanted to check the control box output. I only seem to be getting 12.5-12.8V at the battery or the control box. The cut-out circuit seems to be ok. It operates at over 12.5 V. What should the controlled charging output be? I can't find it in my manual - only for an alternator and I have the dyno. Any suggestions?

[billwill]

At a guess your dynamo probably needs servicing. The commutator can get mucky.

Clean with fine sand paper not emery paper & use an air blast to blow away the sand.

Fit new brushes, your might have worn down to the end.

Clean the contacts in the controller with switch cleaner solution & very fine sandpaper, but avoid moving any of the adjusting screw.

Check that all connectors in the dynamo circuit are clean and firm.

[neilsjuke]

Pull the two B terminals of the control box and link ,put a voltmeter between earth and the D terminal left on the c/box and at 3000rpm you should have 14.5 to 15.5v. if not pull the D and the F off the c/box link then v/meter onto the pair and to earth and rev for a short time and you're look to see the voltage rise above 16V (note do this for a short time as now unregulated and voltage will rise until the armature overheats and throws out the solder .
Neil
As for cleaning armatures if no wear that would need a cut in the lathe then back cutting the mica between the segments scotch brite is the way to go nowadays

[Boston-Sam]

Last weekend my car was running beautifully. On Sunday when I tried to start it, after the motor turned over a few times, the dashboard went dark and all power appeared to be dead. I first checked the battery (as that seemed the least common denominator) and saw the date code (more than 10 years old) must be the problem.

With a new battery the symptoms are the same.

Fuses are not blown and it appears as if power gets to the solenoid because when I take the cover off and push the plates I see a spark.

Are there other fuses or connectors that are likely culprets?

'67 S4 DHC

[neilsjuke]

Check the battery terminals and lead to earth/chassis , solenoid terminals.
Neil

[Boston-Sam]

Thank you - it does appear to be a grounding/earth problem.

Is there an s4 wiring harness diagram posted on the web?

Where should I look for the ground point for the solenoid?

[neilsjuke]

Black earth wire on to fixing screw/bolt on solenoid
Neil

[Boston-Sam]

Thanks very much for the help.

All ground/earth connections tested so far are good (zero resistance on an ohm meter from post to chassis). Still probing but I suspect a short.

[neilsjuke]

Check for volt drop take battery volt readings from the battery solenoid and at starter, put volt meter on the terminals of the solenoid whist in start and check for voltage less than 0.5v also check the chassis to engine earth that dose not follow the fault you described with the dash lights also check the dash earth on the lower fixing bolt.
Neil

[Boston-Sam]

Turns out the failure was in the voltage regulator. While waiting for the part what is the risk of running without one?

[Galwaylotus]

Turns out the failure was in the voltage regulator. While waiting for the part what is the risk of running without one?

You may cook your battery!

[neilsjuke]

You can run with out the control box link the two B Browns .
If you are leaving the box on pull the F & D wires to dynamo
Neil