Don't like the adverts?  Click here to remove them

1978 FJ; no electrical power

Shawn Thissell

New Member
Joined
Dec 12, 2017
Messages
4
Country Flag
united_states
Not sure if I'm in the correct forum, please redirect if not. I took my 1978 FJ40 off the road about 5 years ago due to various issues and was also experiencing serious ignition trouble at the time (very choppy). I have just reanimated it with a new HEI but have now power to lights, starter, heater etc. The car runs perfect. I have been through the fuses, ignition switch and engine grounds. Is this caused by bypassing the original ignitor circuit? Any troubleshooting direction is appreciated.
 
Hi Shawn, I'm not sure if the 40 series has them, but other trucks such as the 80 series have fusible links attached to the battery +ve terminal that go to things like alternator bolt sense, auxiliary fuse box and the like. Have a look and see. I'm sure somebody will be along soon who knows more specific info about the 40s. You're in the correct section BTW, it's just a good idea to pop over to the 'introduce yourself section' and say Hi, tell us a bit about your truck and post up some photos of it. We love photos on here, especially 40s. This is a really friendly forum with loads of info and helpful members. You've come to the right place. :)
 
Thanks StarCruiser, I don't recall seeing a fusable link at the battery. I'll trace it back. I'll also upload some pics. I'm working on my second restoration this winter and may need some info as things progress.
 
General troubleshooting:-

Test at the fusebox with multimeter set to DC Volts with the -ve on the -ve battery terminal. Result A, + 12V = test with -ve lead to a good body earth point. (C)
Result B, = zero volts, look for a break between battery + and fusebox.

Test (C) as above,
Result A = + 12v, then look for a break from the fusebox onwards.
Result B, = zero volts, check earth strap from battery -ve to the vehicle body. Put multimeter +ve on +ve battery terminal and use the -ve lead to test on all the body panels on a known bare bit of metal. You could also do this by putting your multimeter on continuity or Ohms and testing between battery -ve and each body panel in turn. You should get close to zero for good connections and a high reading for poor ones.
 
Last edited:
Good luck shawn, you have all the experts at your fingertips so im sure they can get you going. Lets have more pics though so we can see the issues.
Nice to have another 40 on board
 
Hi Shawn, Looking in my manual the fusible link feeds to the ammeter and on to everything else that you mention as not working. It should be situated very near the battery terminal and the main cable feeds the starter and engine. If you need a wiring diagram I have one that I can scan and post on here (it is for 1977 onwards and for USA & Canada vehicles).
40 fusible link.jpg

Regards,
Rodger
 
Don't like the adverts?  Click here to remove them
Ben, Rodger and Starcruiser, Thanks for the support and info. I hope to get the 40 out of the weather and start troubleshooting over the holiday. I suspect the fusable link wiring is the issue. I'll take a closer look and get back in touch. Thank you.
 
Back
Top