Momentary radio and A/C cut while driving

Hello,

New member here. My wife's TRD Off-road recently has a weird issue. While driving the radio and A/C will cut for less than a second, then the A/C comes back and radio resets. This happens maybe once or twice in a twenty minute ride. Battery is pretty new and never gave us issues. Any ideas?

 

Have you checked your battery terminals?

 

Yes, they are both tight. What's weird is both A/C and Radio go out, but both are on different relays.

 

Besides tightness, I would check corrosion. The thinnest layer can cause issues.

Batteries regardless of age also do really strange things to vehicle electronics when they begin to fail, I'd also check the battery as well.

I know these are "duh" kind of things but I've solved so many weird electrical gremlins starting there.

 

No, that's a good point. If the problem persists over the next few days, I'll get someone to scan the ECU via the ODBII port. I actually don't know much about this truck since it's my wife's vehicle. She drives a lifted 4Runner and I drive a lowered/tuned Evo. We are at opposite ends of the automotive spectrum. But I guess if everyone was the same, life would be boring.

 

Electronic gremlins can be a real pain to chase down for sure.

It seems to me after reading many posts on electrical issues that our vehicles are very sensitive to an underperforming battery or alternator. Also grounds that have been compromised can cause problems.

 

I'll come back to this post to follow up with what we find (if anything). Nothing worse than abandoned problems on the internet that help nobody.

 

Does her 4Runner use a regular key?
I've seen this on other vehicles that use a key switch, it gets a little play in it. Then if the drivers key chain is heavy it swings while driving and you lose accessory power.

 

That's good insight. She uses a regular key, but the vehicle is pretty new and everything seems pretty solid. So weird that both the AC and radio cut out for an instant. No other gauges go out as far as I can tell. I'm trying to capture the behavior on my phone, but it is tough to record. My wife insists of blasting Enrique Iglesias on the radio all the time, so I'm mostly covering my ears when I travel with her.

 

OK, I've got some good news for anyone with this problem. As it turns out, the battery connection was not on fully tight. It was tight enough to not be able to pull off, but you could (with reasonable effort) twist it on the post. So, it was tight, but not super tight.

This was enough to periodically cut power for a fraction of a second. Tighten down your posts on these vehicles is the lesson learned.

 

My runner is doing the same, although it’s only when I hit my brakes. The engine doesn’t stall or anything. It’s been below zero at night here a lot, but it starts every morning without hesitation, so I don’t think it’s a weak battery. It might be one day a month, but it does it in clusters. Could really use some more suggestions.

 

If your battery is at least 3 years old, it’s the first culprit you should suspect. Have it tested.
Also check the battery connections. And the alternator output.

 

So I decided to take a look at the battery connections even though they looked good from the outside. When I got them off I was flabbergasted with how much corrosion there was! Got everything cleaned up really well, and was really surprised by just how much effect it had. I’ve driven it for a couple of days and I haven’t had any more problems. Crossing my fingers.

 

So I have been battling this issue with the radio rebooting and my HVAC H/U rebooting at intermittent times, more often during turns and bumps. Sure enough I looked at my battery and my J-bolt was missing and the top bracket was sliding around arcing out on my positive battery terminal. Fingers crossed that this has been my issue.