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Discussion Starter #1
I have a 99 rav 4 door 2wd version. I have an issue where when it is very hot outside I have a major electrical failure of some sort. The following stop working when this occurs: All windows, windshield wipers, blinkers (4 ways work though), radio, heating/cooling system, the speedometer, the tach, the odometer. However, I can start the car, I have to use shift lock button to get transmission in gear, once in gear it works fine. Interior reading lights works, power locks (including car alarm key fob), door chime and a few other things work. I did not test power mirrors.

Any idea what would have to fail to take out all of these systems but leave others still intact? This has happened twice. Once it fixed itself quickly (within a minute). The second time (today) i ended up driving about 5 miles and the systems finally came online. That was a very hot 5 miles with windows up and AC off. Any help would be appreciated.
 

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The Rav4 has 2 big circuits, all that you list as good are on the 80 amp main fuse and all the others go through the 100 amp ALT fuse. Both located on the left side of the engine bay, standing in front looking in.
Bad news is that the 100 amp fuse supplies power to the ABS, seatbelts, airbags, stop lights and such; making it unsafe to drive. Fuses do wear-out over time and yours may be dying or have damaged wiring in that circuit.

A place to start looking, good luck.
 

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Discussion Starter #4
The 100 amp fuse actually looks OK - I pulled it out and ordered a replacement just in case but it looks fine. Where does that wiring go to next? I tired to find a wiring diagram but no luck. Obviously it splits somewhere and the fault is somewhere between the fuse and the split.
 

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Investigation continues. The wire goes to the alternator (at least 1 branch anyway). Tested thr alterntor. Battery shows 12 ish when off. And shows 11ish when running. Alterntor shows the same. Around 11 even when revved. So bad alternator? How could a bad alternator impAct all those systems even when the engine is off?
 

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The power source.pdf is why I suggested the 100A Alt area.

Looking at the Systems Power Source.pdf at the F7 Fusible Link Block near the battery.
I wonder if the problem is in the block? Strange, but it lives by the battery with a lot of heat and vibration. The white wire at pin 6 of F7 leads to the systems you are having trouble with.
The alternator also connects through the F7 block. Look for corrosion or heat damage.

Most part stores will test you alternator and charging system for free, if it is still acting up after you find this problem.

Both files are from the Toyota 1999 Rav4 manual set, as you can see it helps to have the whole manual as they keep pointing to different sections. Ask if this leaves you with some questions.
 

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Discussion Starter #7
I was able to get the full manual by searching the forums (Thanks Pim your profile is very helpful). With that in hand I could eliminate the f7 block as I was getting 12v power to the other relay block #2 in the engine and the e/g main relay. So I think the issue is either the 40 amp main #1 relay, the ignition switch or a wire in between those locations. I did not have time to test them. The alternator has some control inputs coming from different feeds than the main white wire. It appears those are controlled by the same circuit that is not working. So maybe fixing the electrical problem will then better control the energy output of the alternator. Or maybe the alternator is failing too. I would not be shocked to see multiple failures with a car this old and 330k miles.
 

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I can't find the relay block # 2 or the e/g relay on the schematic, so I'm lost.

Good hunting.

On edit: I found the e/g relay, the 40 amp main is on the circuit that was working for you.
When you look at the power source.pdf, it was all the circuits off the 100 amp fuse that quit working for you. If the 80 amp had shut down, so would the engine.
 

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Discussion Starter #9
I was using a schematic from what must be an earlier version of the Rav. However in Both diagrams The E/G main relay is fed from the white wire off the 50 amp HTR fuse which is tied to the 100 AMP ALT fuse. The white wire comes into junction block #2 and splits. I have verified that it is fine to this point. One of the splits eventually goes to the ignition switch. Opened the steering column and tested the white wire there. That one is dead. So the ignition is not the issue.

In the diagram I have that wire goes to JB 1, runs through a 40 amp AM #1 fuse and then out to the ignition. However, in reviewing JB #1 today it looked nothing like the diagram I had. If found a fuse document for 99-00 that shows the JB #1 that I have. Based on that and the document you provided it appears the 40 amp fuse has been removed in the 99. In your diagram it looks like the wire goes straight from JB #2 to the ignition. Is there any other documentation that confirms this? I assume it still when through JB #1.

So right now my theory is either that wire between JB#2 to the ignition is broken if it goes straight or either of the white wires going into/out of JB 1, or perhaps JB 1 has some cracked solder joints. Hopefully I will have a answer tomorrow as I test all of these options.
 

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The documents I linked to this post are from my 99 manuals, you said yours is a 99.
Why are you using a schematic for an earlier Rav4?
 

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Discussion Starter #11
Well I figured it out and was a bit shocked with the result. I finally figured out that the wire runs through the 10 amp AM 1 fuse on JB1. Not sure why I missed the earlier on your drawing. Tested the link between the fuse and the ignition at it was fine. The fuse tested OK but there was no connection from the fuse to the other Juction Block. Found the white wire that runs between the blocks and that tested fine too. So I pulled the block which was a pain and opened it up expecting to see a broken solder joint. Well unfortunately as I open it up it starts to leak. When I finally get it open it is very clear that it has been wet for quite a while (see pic). The post where the 10 amp fuse connects rusted off. No way to really fix this other than buy a new block. No idea how this got wet but I guess something leaked at some point in the past. Hopefully the new block solves all problems - although it is $300 for the part...

https://drive.google.com/open?id=0B9Q4YS2HSztUWnRFZktyVDN6RFJxNzBncEVZN0NtVlduRVQ4
 

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It would be interesting to know how it got wet. Sort of the modern day equivalent of what Lugnut suggested.

The drawing does have a lot of information and sometimes it is hard to follow. Having the whole manual helps as it has sections that explain everything on the drawing, the book is over 200 pages on just the wiring for a 1999 Rav4.

Toyota parts are expensive, have you looked for a used one?
Should be an easy fix once you have the part. :)
 
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