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Ignition warning light remains on and headlights come on

Tomblin

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Recently, I needed to rebuild the engine in my BJ8 and therefore took advantage of this to upgrade the wiring. Following the advice of several posters on this site, I modified the headlight circuits to include relays. After, reinstalling the engine and a bit of recommissioning everything is running great, with the exception of two issues. First, the ignition warning light remains on after starting and in fact increases brightness as the RPMs increase. This suggests to me that the warning light circuit is “seeing” the current from the generator when the generator is at full output. My understanding of the control box. Second, the headlights come on when the generator kicks in regardless of the status of the dash switch. The dash switch does control the pilot, taillights and head lights when the engine is off. When I start it, the headlights don’t come on until the engine engages suggesting that the current is coming from the generator. I’ve tested the generator by pulling the leads to the D and F and bridging these and then measuring the voltage with the engine running. As it should the voltage builds well above 12. Also, I can see charging on the battery when the engine is running. Given that I see both the ignition warning light and the head lights on when they shouldn’t be I am pretty sure these are caused by the same thing. It seems likely that there is some wrong in the current/voltage control systems. The warning light usually comes on when the voltage in the white wire coming from the starter switch is higher than the voltage in the brown/yellow wire coming from the D terminal on the generator. It seems that this light could also come on if the balance went the other way. The box is fairly new, but perhaps I need to swap in a new one. Is there any other possible cause of these problems?

Bruce
 

RAC68

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Hi Bruce,

I have a suspision that the issue you are experiencing is related to your implementation o headlight relays. Can you please provide a schmatic of your wiring implementation (hand drawn would be sufficient).

Ray(64BJ8P1)
 

John Turney

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If I read the wiring diagram correctly, A brown/yellow wire from terminal WL on the regulator goes to one side of the warning light (providing generator voltage) and white wire from terminal 2 on the ignition switch goes to the other side of the warning light (providing battery and load voltage). If the light increases in intensity with the generator output, my guess is that the white side of the warning light may be grounded, instead of coming from the ignition switch.

As Ray requests, how are the headlights/headlight relays wired?
 
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Tomblin

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Ray

Thanks for your thoughts. With regard to the warning light and possible grounding of the white wire running to the ignition switch, I'll need to go check this and get back with you.

Regarding the wiring of the headlight relay. I've uploaded a diagram of the headlight circuit with the relays included. I should say that the car is positive ground. Basically the relays are taking a signal voltage from the dip switch at terminal 85 along with unswitched power at terminal 30 coming from the brown wire at the solenoid. I wondered if the relays were the problem and so I ran a test with a jumper wire running from the light switch directly to the headlights by passing the dip switch and the relays and I still had the same problems. This test didn’t take the current feed to the relays out so perhaps that is where the problem lies.

Bruce
 

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RAC68

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Hi Bruce,

Sorry for the delay in my response.

After reviewing your scamatic, I see no issue in your wiring diagram. That result gives me the suspission that the issue is and unintended consiquence resulting from a possible bad ground. It is not uncommon for a missing or faulty grounded circuit, given sufficient power, to find an unintended alternate path to a ground … even through another circuit. This could be what is happening to cause your imbalance that is activating your generator light.

I would first check and/or reinstall the relay grounds. If no change in operation, I would consider isolating the new headlight circuit components by disconnecting their power sourced from the solenoid line. If the generator charging light performs properly, I would consider reconnecting the solenoid's power source and replace the relays, one at a time, with a validated relay replacement, checking the generator light operation between replacements.

My thoughts. Good luck,
Ray(64BJ8P1)
 
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Tomblin

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OK, the problem is solved - I think. The basic problem was that the voltage regulator was allowing the voltage from the generator to be way too high. This caused the warning light to be on while the engine was running and I believe the voltage levels were high enough to jump the contacts in the head light relay.


Diagnosis and Repair:

I followed Ray's suggestion and removed the head light circuit from the car. Of course the lights stopped coming on when the ignition kicked in. However, the ignition warning light continued to come on and become brighter as the engine increased revs. The warning light receives current from the battery and the generator. When the voltage output of the battery and the generator are similar, they cancel the current and the light should go off. If the generator is putting out more than about 14 volts, it is likely to overwhelm the battery that is around 12 volts and the warning light would come on. Given that the light was varying with engine speed, I suspected that the light was getting too much voltage from the generator. The voltage output of the generator is controlled by the voltage regulator that is part of the control box. The voltage regulator is supposed to feed current to the field coils I have a DC variable bench power supply, so I pulled the generator out and used the power supply to simulate the generator. With the ground (positive in this case since I have positive ground) on the frame and the negative feed on the D terminal of the control box and the ignition switch on, I increased to the voltage past 14 volts. The warning light glowed and increased in brightness as the voltage increased which supported the likelihood that it was the voltage regulator. This strongly supported the idea that the regulator was at fault.

I pulled the control box out and again used the voltage regulator to simulate the generator (positive to the ground tab and the negative to the D) and also put a 12 volt battery (low amps) on the B and ground terminal. The contact in the Control box is on the far left facing the Control Box. This is closed in its normal state and thus, allows current to flow to the field of the generator. As the voltage of the generator increases it increases the flux field of the coil and with sufficient voltage the points open. The points need to be adjusted so that they open when the voltage coming from the generator is between 12 and 14 volts. So I needed to adjust the points. I released the nut on that held the contact point on the regulator in order to allow the points to be screwed in and out. I connected a Volt Ohm meter to test the continuity between the points. I then adjusted the gap distance by turning the point screw so that when I increased the voltage from the power supply the points opened above 12 volts and below 14. Then I locked the points down with the nut. I installed the control box in the car and started the car and the warning light flashed on at the beginning of the start and quickly went off when the engine came up to speed. Also the with the lights wired back in, they didn’t come on.
 

RAC68

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Hi Bruce and CONGRADULATIONS on your achievement.

Keep in mind that most have never adjusted a voltage regulator (including me) and when facing the necessity, chose to replace the unit. I aplaud your investigation of the device and addressing setting it up as required in the early days of the car. Healey electricals are somewhat straight forward and logical as apposed to modern electronics. However, a mixture of both types of devices will gain you far greater reliability and operational performance then their original counterparts. Such examples of this is when we add a Transient-Voltage Suppression (TVS) diodes to a points driven SU Fuel Pump or, in your case, relays to the Headlight electrical setup.

Good job and all the best,
Ray(64BJ8P1)

 
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Tomblin

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I hadn't messed with the control box either, so it was a bit of an education to try this. I thought about pitching the control box and buying a new one, but actually the one I had was fairly new. Moss has a set of videos that discuss the working of the control box and in it the guy says that these are not plug and play and that you need to adjust the voltage regulator. Since I got mine from Moss, I figured they expected me to do this. Actually, I'm back to resetting it again because after installation and what seemed like good performance it started to go back to lighting the warning light when the engine was running. I tested the voltage coming from the generator and it had drifted up to around 20 volts. My guess is that the adjustment screw was not locked down enough. So, I'm going to try again and this time use some loctite. If that doesn't work. I may, as you suggest, just bite the bullet and get an alternator since that doesn't require a control box. Unfortunately, I have stayed with positive ground and so alternators for positive ground are pricy.
 
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