Original submission made by T Dec 25th 2005:
- 1 Dim Lights, Slow Wipers, Cranky Starters, Undercharged Batteries. Causes and Cures:
- 1.1 Alternator Feed:
- 1.2 Generator Feed:
- 1.3 The Primary Feed:
- 1.4 Chassis Ground Cable:
- 1.5 Engine Ground Cable:
- 1.6 Glowing Charge Light:
- 1.7 Blowing Instrument Fuse:
- 1.8 Fusible Link:
- 1.9 Starter:
- 1.10 Battery:
- 1.11 Alternator:
- 1.12 Earths:
- 1.13 Tail Light Earths:
- 1.14 The Charging System:
- 1.15 Red/Blue/Black Six Cylinder Engine Ground Bolt:
- 1.16 Links:
- 1.17 Terms:
Dim Lights, Slow Wipers, Cranky Starters, Undercharged Batteries. Causes and Cures:
Qute has provided some of the finest examples of the relevant wires. The condition these wires are in is a classic example of the state which causes Dim Lights, Slow Wipers, Cranky Starters and Undercharged Batteries. Fuse Cover Thread These conditions are not unique to Old Holdens. If your cables look like most of these they are overdue for replacing. See also Electrical Tips.
This is the large cable that connects the Alternator to the Battery. Any voltage drop across the Alternator Feed is a direct cause of dim headlights, slow wipers poorly charged Batteries. In the example below, a burned Alternator Feed results in the Battery being deprived of the 14V it needs to be charged properly.
The effect of both a burned Alternator Feed and a burned Primary Feed can destabilise the electrical system and combine to produce very dim lights and very slow wipers. When the cables are burned the copper will be oxidised in appearance, the insulation will be hard, brittle and it will have shrunk at the connectors.
Replacing these cables with new ones of the correct current rating will return the voltage drop along them to an acceptable level. Since the Alternator Feed is the hardest working electrical cable (in a normally functioning car, engine running) because the power for every electrical device on the car will come through it, the effect of heat will can cause it to oxidise and need replacing in time.
When the engine is shut off, the battery provides the power. After a start the alternator feed has to run every electrical load as well as replenish the battery Consequently there are circumstances where the car's electrical load, plus the load of the discharged battery can exceed the current rating of the alternator.
At this stage the alternator is described as being in "current limit". Once the battery has been recharged, the current flow from the alternator will reduce and the current flow through the alternator feed will also diminish. As a consequence, the current rating of this cable must be at least equal to the maximum output of the alternator. i.e. If the alternator is rated at 85 amps max, the alternator feed must be rated at 85 amps minimum.
To protect against over current (in the event that a short circuit occurs inside the alternator) the alternator feed should be protected by a fusible link equal in rating to the alternator's maximum current. 3 x 30 amp wires each with a 30 amp fusible would do the same job. As a car ages, this cable can become burned and resistive, due to the load it carries and under bonnet temperatures.
As a result critical voltage will be lost across it and replacing it with new cable will fix the voltage loss. A badly resistive Alternator Feed can cause a glowing charge indicator light because the current will flow up the indicator feed wire from the alternator to the indicator dash bulb.
The largest wire that runs from the Generator to the Regulator is called the Generator Feed. Another wire of equal thickness will exit the Regulator and run to the Battery Positive Terminal. Both these wires must be at least equal in current rating to the Generator's maximum output and the Current Regulator must be seet to allow this current to pass. The Generator requires a matching Regulator to work properly and these considerations should be provided for when adjusting the Voltage Regulator, the Current Regulator and the Cut Out Relay. All wires between the Generator, Regulator and Battery must be able to carry the current that will flow through them to allow the Generator to deliver its full output voltage and current. Of particular note is that the Generator Feed is most likely to age and become resistive first. The same requirements mentioned for Alternators hold true for Generators too i.e. the Generator feed must be rated to carry at least the maximum output current of the Generator.
The Primary Feed:
This is the second hardest working cable in any car and early Holdens are no exception. Certainly up to HZ the headlights wipers, ignition, horn, tail-lights and brake lights are all run from it. Any voltage drop across the Primary Feed is a direct cause of dim headlights and slow wipers. The Primary Feed is the lead that runs from the large Starter Tap to the Fuse Box under the dash in Kingswoods and Toranas. Over time this wire becomes resistive and a voltage drop appears there. On Kingswoods and Toranas there are additional taps on top of the fuse box that provide connection for additional Primary Feed wires.It's best to relocate any connectors using these taps to other locations, perhaps direct from the Starter Feed.If the load on the Primary Feed is increased (by adding a hi-fi system, dash fed driving lights etc) it is imperative to uprate the current carrying capacity of the primary feed to accomodate the extra load otherwise the life of the Primary Feed will deteriorate. As a car ages, the Primary Feed can oxidise and become resitive due to the load it has carried and the under bonnet heat.
Chassis Ground Cable:
The Chassis Ground Cable carries all the Body return Current. Lights, Radio, Wipers, Internal Fans, Thermo Fans etc all send their return Current through the Chassis Ground Cable. Starter and Engine Current returns via the Engine Ground Cable.Make sure the Chassis Ground Cable is large enough to carry all the Electrical Load except the Starter Current.I recommend using a separate length of Starter Cable connected between the Chassis and the Engine Ground Cable to make sure the return Current does not cause a large Voltage drop or burn any wires.
Engine Ground Cable:
The large cable that runs from the engine to the battery negative. This has to be large to carry the starter current. It also provides the return path for ignition and any engine sensors (oil, temp etc).
Glowing Charge Light:
Extremely burned Primary Feeds can result in a glowing Generator Light on the Dash which is caused by currrent flowing from the Alternator to the dash because the Dash voltage is lower than the Alternator voltage. Fuse Glow Submitted by T on Sat, 24/02/2007 - 12:19. If the particular car has a Fuse Panel that uses an Instrumentation Fuse, and it gets rusty, then the Alternator Light can be caused to glow when the Engine was running. Under this condition the Alternator Light would provide a reverse current flow from the Alternator in pollution models like HZ's, UC's and VB's and the Alternator Light could glow because the Anti-Dieselling Solenoid and Transmission Control Switch would provide a ground path for it in the absence of the system voltage at both ends of the Alternator Light. Models that don't use an Instrumentation Fuse won't do this because the red and pink wires are direct connected in the Ignition Switch giving both wires the same potential. T
Blowing Instrument Fuse:
Any voltage drop across the Primary Feed is a direct cause of dim headlights and slow wipers. The effects of both a burned Alternator Feed and burned Primary Feed can unstabilise the electrical system and combine to produce very dim lights and very slow wipers, weak ignition, dim dash lights, dim tail lights, interior light. Indeed any load that connects to this wire. The top of the fuse board (particularly on HZ's and UC's) provide spade connections for additional primary feeds. Additional Primary Feed wires have one end connected to the large connector on the starter by a fusible link and each other end connected to one of the spade connectors on top of the fuse board. The additional current carrying ability will prevent the lights dimming and the wipers slowing down amongst other electrical loads that are fed from there. Additional Primary Feeds should be 30 amp cable fed by a 30 amp fusible link connected to the starter tap.
I use this Fusible Link mentioned in Thread 1. If the above links to Dick Smith are broken, the part number for an inline blade fuse holder is P7907, and a waterproof and screw mountable version of the blade fuse holder is part number P7909.
Oxidised Starter Cables can cause problems that may appear to be inside the Starter. They include a Slow Cranking speed and the Starter Solenoid Clicking. Weak Electrics can also deteriorate the life of the Starter Ring Gear. This occurs because insufficient Electrical Supply will cause the Starter Pinion Gear to lose engagement whenever the Starter encounters Engine Compression. Pinion Gear cycling will seriously reduce the life of the Starter Ring Gear by ripping down the face of the Starter Ring Gear.
Battery:A High Capacity Battery is the best investment for long Battery life and minimum Electrical problems. Battery connections must be clean, tight and covered by Electrical Grease otherwise Starting and Charging problems are assured. Battery section for further info.
The Alternator must be able to carry the entire electrical load of the car plus have capacity in reserve for recharging the Battery after a start. Over the life of a car devices can be added which can exceed the Alternator's rating so it's important to measure this load and provide for it. A dash mounted Voltmeter is invaluable when it comes to monitoring the Alternator's performance. See the Alternator Alternator section for further info.
The Chassis of the Car is sometimes called "Earth" or "Ground". Leads that connect direct to the Chassis are called "Earth Leads" or "Ground Leads". There are 2 critical Earth Leads on an old Holden.
One is a cable of at least 200 amps rating that connects the Battery Negative to a bolt on the Engine's Cylinder Head (on 6 cyl engines). This is the Engine Block Ground cable. The other lead runs from the Battery Negative Terminal to the Car's Chassis and as standard is often only rated at about 50 amps. This is the Chassis Ground cable. It is vital that both these leads have clean and tight connections since the absence of either of them can cause serious damage to the Car. If the 200 amp Engine Block Cable is missing or loose, the Starter Current will have to find a new return path to the Battery and will be only too happy to connect through every Gear and Bearing in the Gearbox as well as Universal Joints and Gears and Bearings in the Differential in addition to the Wheel Bearings at least until the Chassis Ground burns out. If the Chassis Ground is missing or loose, Electrical Loads in the car will travel from the chassis through the transmission and back to the Battery via the 200 amp lead. The Chassis Ground cable should carry a rating at least equal to the total Electrical Load of the car excluding the starter current. My cars carry 100 amp Chassis Ground cables. Needless to say in either case Gear Pitting can result. Some folks advise fitting a 3rd Ground Strap (of 200 amps current rating) that connects the cylinder head to the block. This lead prevents the Head Bolts and Head Gasket from carrying the high current passed by a Cranking Starter from the Block up to the Head which might cause any burning or corrosion there. As with the Alternator Feed and the Primary feed, these cables age through normal use, Engine Heat and any overloading they've been exposed to. If they look old and burned then replacing them can pay an Electrical Efficiency dividend and increase the brightness of dim lights and the speed of the wipers.
Tail Light Earths:
Corrosion and moisture can prevent the rear lights from working properly.