2H 1984 HJ47 Electrical System Problems (1 Viewer)

[samp]

Hello,

I have a 1984 2H HJ47 with the following problem. The voltage on the key switch at the ACC position reads the full battery voltage, however, whenever I switch to IG (ON) position, the voltage at the IG connection drops to around 5V. This results in many of the lights not working and the car being reluctant to start. The problem stops when I remove the engine fuse of the car, which results in the glow plug indicators not lighting up and the voltage at the IG connection (at the key switch) being the full battery voltage.

I know the connection from the engine fuse goes straight to the voltage regulator, is the voltage regulator faulty or is this a problem with the glow plug circuit. What should I test next to find out?

Would appreciate a response, Sam.

 

[duncanrm]

What is the battery voltage when your measurement at IG has dropped to 5V?

 

[samp]

It is also 5V. Measured directly at the terminals of the battery

 

[duncanrm]

Have you had this battery load tested? Alternatively.. if you (safely) bridge out the starter motor to force it to crank - does it do so at a good speed? For your battery to drop to 5V you have a MASSIVE load on the system.. or the battery is toast.

 

[AussieHJCruza]

If the battery voltage is dropping to 5 volts, I would say it is likely the culprit.

 

[samp]

Guys thanks for your suggestions. I have since solved the problem.

The problem was two fold. 1. The insulation on the alternator had failed and current from the battery was going straight to ground through the alternator. 2. One of the two glow plug relays wasnt opening after a the pre heating cycle, so I wired it in parralel with the one which was working and my issues are resolved.