Two years ago, my recently-purchased FEH threw a rod. I had it towed up to my garage and there it sat for the last 18 months until I found a scrapyard engine to swap. I dumbly did not disconnect the 12v battery while it sat Anyway, I just finished the engine swap, but I cannot get any signs of electrical power anywhere in the car.

I am sure that the 12v battery is good (just bought it and it drove me home today in my other FEH), and I have a charger that has a "jump" setting that I've hooked up to it--no dice. I tried the "jump" setting on my 2008 FEH and it was sufficient to power interior lights and dashboard, so I'm certain that the 12v battery is not the issue.

It is possible that I missed an electrical connector when installing the new engine, but very unlikely because (1) I labeled all the electrical connectors as I disconnected them and (2) I was very deliberate to make sure I connected all of them fully.

The HV battery is surely very dead--would this be sufficient to prevent all power to all systems?

It could also be fuses, but all the ones I could find that might affect the entire electrical system looked good. I didn't find a fuse for the 12v battery, though. I do have the user's manual and don't see anything listed for the 12v battery.

Does anyone have any ideas what I should try to get some power to the car? Right now, nothing at all is receiving any.

 

I have no idea on the FEH, but just checking the fuses you THINK could be the culprit assume you know what you're looking for.. Check ALL fuses. Check continuity, not just visual.

There's a single fuse in a Prius that will do exactly as you describe - ONLY the dome lights and headlamps work. Dash is completely dead, No start. No nothing.

I'm a little confused. "prevent ALL power to ALL systems?" DId you just say you have dome lights and dash lights, or was that in your "other" FEH.

You have posted concerning an '05. Which vehicle are we talking about?

Have you load tested the new 12V? New doesn't mean good.

Corroded terminals? Bad battery cables?

 

Sorry, I wasn't very clear. I have an engine-swapped 2005 FEH and a functional 2008 FEH. The problem is with the 2005.

There is no power anywhere in the car--no dome lights, no dash lights, no horn, nothing. Completely dead. Nothing happens when I turn the key. I am fairly certain the problem is not the power source (battery).

There are 2 batteries I've used here: the one that was in the car for 2 years (which I did load-test and it passed) and the new one (which I didn't load test but it started my other FEH up multiple times without problem). And I have used a "jump start" charger hooked directly to the cables with the same result (nothing happened). I tried the jump start charger on my 2008 FEH and it lit up the interior lights/dash, so I know it provides sufficient juice to see at least some effects.

Could a dead HV battery cause the symptom I'm seeing?

As for the fuses, I guess I will check all of them, but it doesn't make sense to me to check the individual fuses--if you pull the fuse for the headlight, for example, the whole electric system doesn't turn off. But I don't know what else to try. Would it make sense to check the relays? If so, do you know how to go about that?

 

I would not expect a dead HV battery to cause this.

I test relays by applying 12V to the coil terminals and see if the relay opens or closes as intended.

 

There's an underhood relay box with something like six identical relays. It was recommended on this forum to carry a spare relay to swap in for troubleshooting. It's a cheap plugin relay available from Ford and probably Amazon. You might research that possibility.

 

Thanks for the suggestions. I took a relay from the radiator and tried it in all the fuse box positions to no avail. However, while I was doing that, I noticed that the ground cable was not connected to the fuse box So I dug around and saw that when I removed the fuse box (to try to create more space for removing the engine), it had fallen and landed directly on top of a plastic screw. So it didn't look like it was dangling and I didn't re-attach it. But I put it on and the car now has juice.

Also started it for the first time in 2 years yesterday and the new engine works! Have a coolant leak to solve now...

 

you let the HV battery go flat

you need to replace it

 

Wow. Did you bother to read anything?

 

Actually the hybrid battery charged just fine once I got the engine running after 2 years of sitting there.