Hey there,

I have a 2004 V8 4Runner that I need help getting on the road again. I drove the truck all day today with no issues. I get home after errands and go to start the truck about an hour later and nothing. No clicking, no lights, nothing. However, I notice that when I put the key in ACC lights come on (very faintly), but when I put it into the ON position everything goes blank.

Took the terminals off and cleaned them. Nothing. Eventually the truck gained a little more power and I was able to track down crazy noises coming from the engine bay. Pulled out fuses until I heard silence. Which ended up being the big pink and blue relay labeled TRC MTR and ABS MTR. Not sure how this all relates which is why I am here...

I had the fuses out and wanted to see if the truck could gain power again and potentially get it to start and cross off the relays as the problem. However, while waiting the truck started flashing lights in the dash and the horn was clicking/honking very faintly repeatedly. I have no idea what is going on and don't even know where to begin. Any insight or help is greatly appreciated!

First Step - have the battery tested, AutoZone/Advance Auto will do it for free.

^^This.

Second step - check/replace alternator brushes.

I agree with this. Low voltage makes everything go a bit haywire. The days of it just making the starter relay make a strange buzzing noise are long gone.

Don't forget it could also be an unstable voltage, again a new/tested battery will help rule this out.

Pink and blue relays are for the brake booster pump.

Which is why all of this is so puzzling to me.

Took the battery to Autozone this morning. Battery was toast. Could tell is was going to be the culprit once I got the battery retaining bolts off and there was corrosion.

Getting a new one put in after I install a new PS pump. Will come back with updates afterwards.

Like stated above^ Took the battery to get tested and it was donezo.

Installing a new PS pump today anyways, so once it's put together I'll come back with updates. Still puzzled that the battery would through all the relays and electronics for a loop. But I guess I'll know the answer once a new battery is installed.

With the electronics in vehicles today low voltage make them do very strange, abnormal and unexpected things that they would not normally do!!

It's not like a electric motor that will just run slower or not work at all.

That's why when strange electrical things start happening, the first things to check is battery and it's connections, then alternator, then fuses in that order.

Relays are likely not receiving enough voltage so failures will seem random. Anyways, you found the issue. Recommend you get a $10 DVM from Harbor or Amazon so you can measure voltage yourself.

PS Pump installed and bled. New battery installed.

Seems to be all good again. Thanks for info everyone!

Curious as to why a new PS pump was needed? Was yours groaning or something?

As stated above, I'd purchase a DVM (digital volt meter) to leave in the vehicle for any future troubleshooting on your or someone else's ride.

I added a dual USB port connector that also happens to have a voltage gauge. Very nice to see what's going on with the charging system.

Got pics of that?

Sure. I removed the lower useless door on the center dash to ft my backup camera. I had extra space so glued a piece of plastic in place for one of these to fit in. Not great looking but super useful. Please ignore the dust.

Amazon.com

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