Battery replacement on recently purchased Prius

The corrosion looks pretty bad, I suggest you also remove the spare tire and look in the tire well as well as in the 12V battery compartment for moisture and rust.

 

Wonder why that one bolt/ nut was so corroded. I think the relays are plug ins. Try reseating, look for corrosion around the base of the relays. There has to be a valid reason why that one place was soo corroded. Maybe p/u some new relays? Did you check the charge level of each battery? Overall it looks clean. Nice pics.

 

. Water leakage was happening on some Prii, either the window gasket or trunk but if one area is bad, other areas should show up, remove the 12v battery and check that well too. Sorry, Pat said that.

 

On second thought, corrosion on that one bolt looks like a combination of oxidation and electrolysis. There is also, what looks like on the flat panel scattered small corrosion (black marks) I would definitely put in a new bolt.

 

4th picture from the top, that plate is heavily corroded ( vertical plate ) maybe the car was flooded. Not that it is necessarily horrendous, a good brass brush and electro clean can fix many things electronic.

 

Yes, that sounds plausible.

 

Great.

 

Hi Heyomateo. Judging from those pictures you posted I'd say the advice from re-involt was pretty good. It definitely looks like the problem could be related to a corroded ground connection. Often something that just looks like a mounting bracket is actually a ground connection as well, so clean up all the corroded bolts/connections you can find back there.

I'd start with some penetrating oil to loosen things up get the bolts undone. Then a good wire brush followed with a clear phosphoric acid based "rust converter" to pacify it. (The milky or black rust converters often leave a coating on parts. Good for continued corrosion protection but they might effect electrical contact).

Reassemble with a light coat of petroleum jelly and then (after you get everything working and tested) spray with an automotive "fish oil" product.

 

04 and newer Prius Parts Cars
eBay:

 

Did you check them to make sure they are bad. I believe the relays are actuated with 12 volts. As for the resistor it's also measurable.

 

While the battery case is open, be very careful of any contact with the battery terminals because of the high voltage. Make sure you have removed the orange traction interlock first.

The system main resistor should have a resistance of 18 to 22 ohms when disconnected.

Regarding the system main relays:

1. Disconnect a relay for testing.
2. Measure resistance of the associated wiring harness to ensure the harness is good.
3. Use an ohmmeter across the relay coil terminals which according to the Toyota repair manual should show 70 - 160 ohms resistance for relay 1; and 20 - 50 ohms for relays 2 and 3. (Not sure why one relay should have higher coil resistance vs. the other two; this may be a manual typo.)
4. Energize the relay coil using 12VDC.
5. Short the test leads of the digital ohmmeter together to see what is the reading for what should be a 0 ohm measurement. That reading should be subtracted from the measurement when you assess resistance across the relay switched terminals.
6. Measure resistance across the switched terminals (subtracting whatever reading you observed from step 5 above.) If the resistance is more than 1 ohm, replace the relay.

 

I would be surprised if the relays themselves were bad, although easily tested as you see. Mechanical relays are extremely reliable and tolerant of abnormal conditions, which is why they are still used (150 year old technology). Since you are at present able to drive the car, you are hearing the relays close as the car goes into ready mode. Click Click......Click from the back seat.

You mention the error light went off. As Uart pointed out, those corroded supports are actual ground returns to the chassis. The relay coils are using this ground return to energize the contacts, and it looks to be marginal at present. First thing is to clean the return contacts to the chassis, and go from there.

 

I would give you a general idea, not having one in my hand I don't know how many pins it has. You said that after reinserting the relays the car went into ready OK with no problem, so everything is probably OK. The act of reinserting anything electrical/electronic is often sufficient to commence proper conductivity. If 4 pin, 2 pins carry the DC high voltage forward to the inverter. 2 pins conduct 12 volts thru a coil and close the relay. Some relays come apart and one can see how it's working and reburnish the points. I'm speaking older technology now, and the relays may be solid state. You should hear the relays click when it goes into ready, reseating without POWER is the best thing you can do. I assume you have all the corrosion cleaned off everywhere by now. Rebooting the Power switch and the 12V battery is almost a standard. Since you disconnected the 12V you automatically rebooted. It probably wouldn't hurt to crawl under the car and take a look at the cable assy and especially where it connects into the inverter. If easily accessible clean off corrosion at those connect points ( Power Off ) Also the coils on the relay have a measurable resistance, can be checked with your ohmmeter, if you were testing those would be the 12 V pins. Wish you luck, keep us posted. Also all of this information is accessible on line thru a Gen 2 search.

 

I should have known that Pat and other very knowledgable posters would beat me to the punch, great info everybody.

 

Interestingly, Tesla was the one who invented the relay. After being thrown across the room by mishandling his high voltage, he thought, maybe I can power up this circuit remotely and not keep getting thrown across the room. Hence the relay. There is a special name for it in high voltage circuits which I cannot recall.....we owe so much to Tesla.