PO Screwed up my wiring please help HJ45

[fjdaveinoz]

As the title suggests the PO has completly screwed the wiring in my truck. Its a 79 HJ45 with a 2H fitted. Was going to put this in the diesel tech but it moves way to fast.

1. My Ammeter doesnt work. The WL wire and the black wire are cut as they come out of the harness near the battery. Someone got a pic of the fuseable link setup so as I make it stock again.
I connect the wiring direct to battery with a fuse. Ammeter still not working, im thinking faulty ammeter, any way to test??

2. Battery not charging properly, here im thinking faulty regulator. Alt putting out good charge, battery getting a charge of about 12.4v. Could this also effect ammeter or vise versa?

3. Oil Pressure gauge when key is ON goes straight to over high, start motor and it goes back to no pressure and stays there. Has new sender.
4. edic wiring completly stuffed, will save this for the diesel tech guys

Maybe im best looking for a 80-82 HJ47 wiring harness and starting fresh.
Please help
Dave

 

[Henry James the 47th]

I can help a little...

The Oil Pressure Gauge.

Assuming your new sender is fine (it can be tested using a 3.4W bulb), and the wiring to the receiver gauge is clean, there are a couple of tests you can do on the gauge itself:

1) pull the connector from the oil pressure gauge and ground the terminal through a 3.4W bulb. Turn the ignition switch 'on', and the bulb should light and the gauge pointer should deflect

2) If the first test shows something wrong, pull the instrument cluster right out and use and ohm meter to measure the resistance between terminals 'A' and 'B' (looking at the backside of the cluster, these terminals are the furthest pair to the right hand side, and are directly under the light bulb socket furthest to the right). The resistance between the terminals should be 44Ω.

Also, with the main multi-terminal connector plugged in at the back of the instrument cluster, when you turn on the ignition switch there should be battery voltage present at the aforementioned terminal 'A'.

The Ammeter.

Not much to this one - the fusible link at the battery connects directly to the ammeter, via the WL wire, to the '+' side of the ammeter gauge. In that WL line is a 5amp fuse, so you might want to locate it and see if it is good. From the ammeter the line, probably Black, goes from the '-' terminal on the gauge, back through another 5a. fuse, and on to the alternator and the rest of the electrical system (the 'load'). The ammeter guage itself is a very simply device that is quite unlikely to fail, so i suspect the issue with the non-function of the gauge lay in your fuses, fusible links, or elsewhere in the wiring.

 

[fjdaveinoz]

Once again HJ Thankyou. Your knowledge is outstanding on all things 47.
Will give it a try tomorrow arvo. Do you know where the 5amp fuses are? My connector straight out of the back of the cluster (the 3 pin plug with WL, black and 2 wb earths) goes straight into the harness. Untaped it to where it runs into the main harness and no fuses. I reconnected the two wires where they were cut at the battery, to the battery and have power at the plug. No ammeter action though.
Electricals are such a pita!!!
if you dont mind, ill do your tests and get back to you.

Dave

 

[herbs]

I feel like going for a gravedig here;p. Any luck with this? Not uncommon for these ammeters to be removed from the system, the one in my hj 45 has been totally disconnected, I guess when the alternator was upgraded to a much beefier internally regulated unit.