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So, I was installing a new stereo on my gf's civic today, after I had completed the stereo install I went to test it to make sure it was all working snazzy. When turning the key to engage all the gauges in the cluster started rapidly fluctuating up and down (tach, gas, temp, speed) for about 10 seconds then stop. All that and the stereo doesn't turn on. Ive installed 4 of these in my own civics/integra's, and never seen this problem.

The car starts fine
Battery is connected properly
Stereo connections are correct (all the power and the ground)
Gauges work fine once car is started

It never did this prior to the stereo change, so of course she is blaming me .there was already and aftermarket one in there, but the CD portion of it wasn't working which is why we got a new one. Whoever did the orig aftermarked didn't use a harness so I had to strip and connect the wires together.

Any ideas on what is causing this?

Thanks

 
Rep Power: 235

Usually it's 2 wires behind the radio touching. Stupid question but, did you disconnect the battery when doing the install? If you didn't you probably fried the MCU (Multiplex Control Unit). It's integrated into the under-dash fusebox.

 
Rep Power: 812

well i at least can tell you some part of the wiring is messed up because the gauges only flutter the first time you plug them back in or if the battery is disconnected. which means they arent getting constant power like they should. did you match the wires correctly? not by color, but by function. and im not sure why the gauges would be related because they should not be tied to the stereo. in which case, lazlong's answer makes sense.

 
Rep Power: 0

Quick way to tell if its something you did (which is almost certain): disconnect the radio from the harness. I would be surprised if anything is fried, but do it by the numbers:

First, disconnect the ground from the battery for each step, just to be on the safe side.

Second, you can leave the dash apart while you do this stuff. You don't need to put it all back together until you have a fix.


1) Disconnect the new harness from the car's harness and start. Observe. Does it still act wonky? If yes, then something is messed up in the car. If not, go to step 2.

2) Reconnect the new harness, but don't connect it to the new radio. Observe. Does it still act wonky? If yes, then something is messed up in the new harness you built. If not, go to step 3.

3) Connect the new radio. If it acts wonky, then its something in the new radio. If not, then its fixed.

Look over every one of your connections. I hope you used solder and shrink tubing. If you just used wire nuts or just twisted and taped, yikes, that could be the problem.

 
Rep Power: 235

^^ If done properly, butt-connectors work just fine and are A LOT easier than solder. As stated in the forums before "if it's good enough for the aircraft industry it's good enough for my car".

FYI: Don't solder in flip-flops.

 
Rep Power: 0

True, but the guys doing it in the aircraft industry are actually trained and aren't using the kind of connectors that you would otherwise use to wire your house.

The guys doing on weekends for their car stereo probably do it twice in their life.

But I take your point.

I've done worse with soldering, and I won't admit it in a public forum.

 
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Thanks for all the replys.

It happens even when the stereo is disconnected. And no I didn't solder I crimped them together. Ya i was reading lazlongs answer, seemed to make sense. I didn't think that the stereo would affect anything else in the car. I did get a spark when cutting the ground wire at first from the old harness used on the old stereo. Turns out the ground battery cable had slid back and was touching the battery connector.

If that spark was indeed the culprit, and it is the MCU, what are the options to have that fixed? And is it bad for the car to keep driving it? They only fluster for the first 10 seconds and then work fine.

Interestingly enough, when she went to put the key into her door, she got a blue spark and was shocked. I'm wondering if a ground wire maybe got jostled somewhere in the dash and is messing things up?

 
Rep Power: 0

Well got a new battery which solved the car not starting issue. Also, the spark from cutting the ground wire without the batt disconnected just blew a fuse. Changed out the fuse, and now the cluster and stereo work fine.

Quick easy $4.99 fix