CF1 models: pull-push/rotate switches mounted in separate dash binnacle.
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Ignition light (2w bulb?)

Post by Robin from France » Subscribing Member » Sun Sep 09, 2018 10:49 pm
Joined: Thu Jan 02, 2014 2:17 pm
Posts: 76
Hi,

just a quickie! My '78 cf230 had a gently glowing ignition light with engine off and ignition on, invisible in bright sunlight, which gave me a few surprises this summer, as I didn't notice a non-charging alternator. I replaced it this afternoon with another from a spare dash, which is now glowing brightly as it should. The problem is that my accessory shop only stock 3w and 5w wedge bulbs, which will surely be wrong to replace the 2w original, as it is a part of the charging circuit.

Is this right?

Robin

Re: Ignition light (2w bulb?)

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Post by Phil Bradshaw » Club admin » Mon Sep 10, 2018 12:22 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3669
2.2W capless (504) is superseded by 3W capless (297) for later models with pull-push lights switch. Either will do because the resistance of the unlit bulb makes no difference to the voltage regulator function.

5W side/tail bulb (501) also can be used - most warning lamp diodes can handle more if pushed - but it can be bright enough to be annoying.

Increasing the load on the warning lamp diode sometimes can delay cut-in of the charging circuit after starting until engine speed increases but this may only be noticeable with things like split charge relays powered by the warning lamp circuit. Once the warning lamp goes out the alternator should charge as normal.

(Warning lamp glowing dimly when the engine is running won't be a bulb problem if the alternator and engine earth test ok: the problem more likely will be excessive voltage drop in the wiring and, or, bulkhead connector.)
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Ignition light (2w bulb?)

Post by Robin from France » Subscribing Member » Thu Sep 13, 2018 8:24 am
Joined: Thu Jan 02, 2014 2:17 pm
Posts: 76
Thanks Phil,

I'd better check my wiring and connectors for clean contacts then, as it does glow dimly when running, but not all the time.

Robin

Re: Ignition light (2w bulb?)

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Post by Phil Bradshaw » Club admin » Thu Sep 13, 2018 2:06 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3669
Check warning lamp in darkness with battery fully charged and everything switched on - headlights, heater motor, wipers, brake and reverse lamps etc.

Faint glow when alternator charging (fast idling speed and above, battery terminal voltage 14 - 14.5V steady) can be safely ignored but if the lamp gets brighter with increase in load or engine speed then something needs fixing before it goes terminal.

First check fanbelt tension. Belt dressing spray can be used to ensure best grip - almost mandatory when up-rated alternator fitted.

If something in particular causes the lamp to glow brightly then check that first in case there's an overload condition in its circuit: heater motor bearings dry of lubricant is a favourite even if neither squeals. Wiper motor ground (black wire with eyelet terminal) to bracket bolt above cab engine cover insecure or detached also can make strange things happen (erratic self-park and intermittent slow running can be a clue for this fault).

Common points where resistive connections can cause warning lamp to glow.

1. Brown wire terminals connected to starter solenoid battery terminal.

Pre-insulated crimp terminals should NOT be used (fine for a quick fix but wire support deteriorates leading to strands breaking and eventual failure). Replace any suspect terminals with good quality non-insulated terminals securely crimped to wires with no air gaps within the crimp. See Amp/TE Good Crimping Guide. Can use plain or self-adhesive heat shrink tubing for insulation and cable support close to the terminals.

Also consider overload beyond specifications of original wiring especially the bulkhead connector and fuse box. Too many post-factory additions may require additional fused supplies from the starter solenoid terminal plus relay/s for up-rated headlamp bulbs and additional equipment fed by the ignition switch (additional fused supplies and relays also will prevent tired switches from melting or burning as well as fix voltage drop causing warning lamp glow).

2. Tarnished, corroded or mis-shapen terminals in the bulkhead connector next to the bonnet hinge on the driver side. Thick brown wires are the ones to go for but also check thinner brown+yellow wire (alternator warning).

Larger terminals for brown wires are extinct near enough: badly damaged terminals may be best replaced by good quality butt crimp terminals or soldered splices, e.g. Lineman splice - fix and forget but more free length of wire needed than for crimp butt terminals.

In the socket bend the terminal locking tabs inwards so that wire and terminal can be pulled out into the cab. Enlarge hole in socket as necessary for likely crimp/splice thickness; cut off terminal then pass wire out through hole in socket.

Carefully slice into plug to extricate wire and terminal as cleanly as possible; dipping plug in very hot water for several minutes to soften it or soldering iron applied to terminal can help. Trim wire back to clean strands once free from the plug.

When splice is done (insulate with heat shrink tubing) black silicone RTV or similar can be used to glue wire back in plug so that splice lands in or to the rear of the hole in the socket when plug is refitted. Observe adhesive cure time for maximum strength (often 24 hour).

A new wrinkle: I've found that Q30 Protective Film is good for keeping electrical stuff dry particularly the bulkhead connector. Can be peeled off afterwards if need be.

3. Poor connection/s at fuse box including melted plastic of the fuse box itself due to overload (which can be related to age as well as too many additions) or incorrect fuses 1 and 2 (12-way fuse box). Fuses should be 35 Amp.

4. Faulty ignition switch or harness plug connections. Check for signs of overheating. Bridge fuse 3 (white wire side) to fuse 1 or 2 (brown wire side) to by-pass switch and dash wiring to confirm or discount resistive connection/s.

5. Dash printed circuit faulty (rare). Remove binnacle cover and look through windscreen for signs of printed circuit film damage or discolouration due to overheating or water ingress affecting adjacent tracks.

Image

Disconnect battery before playing with any brown wires!
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

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