Help! Erratic speedometer and headlight dimming issue
 

Hello there-

My wife has a 1997 Honda Civic, manual transmission, two-door hatchback.

Tonight while driving home the check engine light came on and she began experiencing an erratic speedomter, where the speedometer would basically fly all over the place, jumping from like 10 MPH to like 60 MPH, when she was actually never going over 35 MPH. (It even happened when she drove me around the apartment parking lot at probably 5 MPH) She also noticed the headlights dimming and getting stronger, as well as the same with the dashboard lights. Also, possibly related: a few weeks ago (maybe two or three) the SRS light came on. She was planning to take it in to get the air bags checked, but we've been real busy so that was delayed.

Any ideas on what could be wrong? I've searched the forums and Google, but yet to find anything that matched all of her experiences. I initially thought battery, but I honestly know very little about cars.

Thank you for your help! It is much appreciated. Hopefully I provided enough information, but if not, please let me know and I will try to find out for you.

Re: Help! Erratic speedometer and headlight dimming issue (jdettbarn)
 

Bump..I had somewhat of the same problem. My speedo would go crazy, so I swapped the cluster, but the E-brake light flashes randomly and it did that with the old cluster too. My headlights also dim and brighten. Weird.

Re: Help! Erratic speedometer and headlight dimming issue (jdettbarn)
 

Sounds like a bad ground. check on the passengers side of the car on, and kinda behind the headlight there is the main "engine to body" ground mounting point. if that is damaged or even corroded it could be the culprit. The spedo is electronically controlled on 92'+ civics so if it has a bad ground it would jump when ever it made a good connection and fall when it lost connection. That could be what you are experiencing. It could also be the ground that leads directly from the battery to the body also which could make the lights dim. And finally check the alternator. check for proper voltage output (between 12.9v and 15.3), and also make sure the plug is secure on the alternator. If the voltage is not correct it could possibly be the voltage regulator and with the electronically controlled spedo you can see how that could effect it, as well as the dimming of the lights.

Re: Help! Erratic speedometer and headlight dimming issue (EGintegraHATCH)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EGintegraHATCH &raquo;</TD></TR><TR><TD CLASS="quote"> And finally check the alternator. check for proper voltage output (between 12.9v and 15.3), and also make sure the plug is secure on the alternator. If the voltage is not correct it could possibly be the voltage regulator and with the electronically controlled spedo you can see how that could effect it, as well as the dimming of the lights.</TD></TR></TABLE>

A simmilar situation happened to me once, turned out to be the alternator good luck.

I had my speedo jump and go dead like that, It would also blow the #15 7.5 amp fuse under the driver dash, which is the ign power for the speedo, vehicle speed sensor, the electrical load sensor, and one of the o2 sensors. the ELD not having power caused my car to sortof pulse and the headlights would dim. my fix was to replace that fuse, then a while later it did it again, eventually while doing an oil change i found the problem. it was under the intake manifold in one of those terminated plugs, the ign wire was rubbing against the intake manifold bracket and shorting out the circuit. I taped it up and haven't had the problem since

Re: (ccjustin)
 

Alt would be my guess... had the same problem, similar simptoms. Ended up replacing the alternater.

Hook up the battery to a volt meter and it should read somewhere around 11-12 volts. Anything lower is telling you your battery isnt being charged as it should. If you go to autozone or jiffylube or pepboys, one of those places will do it for free.

i'd have your alternator checked out. i had the same problems. my alternator belt got ripped off some how but i drove it around(without knowing) then after i dyno'd my car my car died in the middle of an intersection.

Thanks for all the tips so far!

I'll give them a shot and report back.

Thanks again. It is really appreciated.

I'd check the alternator b4 you check the grounds, it sounds to me like an alternator issue, it's also possible that they're intertwined as in: the alternator failing and the correction of it (the brightening) caused too much power which popped a fuse for the speedometer....so yeah, I'd check the alternator first, if the dim/bright fluxuation goes away, and the speedometer still doesn't work, that's probably just a simple $0.99 fuse, if it still does it it might be a bad ground, in which case you have to do a lil looking around for it...

As for the SRS light, there's a thread somewhere on honda tech that tells you how to reset the SRS system I believe, if not, having it (the battery) unplugged from when you put the alternator in (&gt;15 minutes, hopefully) and when you put the terminal back on the ECU will reset, but that's something you might wanna try even b4 diving into the alternator, just try resetting the system by unplugging the ECU for a half hour or so (I'm not positive how much time it needs to reset, but I don't think it's more than 10 minutes)..

Good Luck

Re: (dohcdelsol)
 

Hey CC-
I'm fairly clueless under the hood, but I'm having the same exact speedometer issues that you're talking about - with the wild spinning. The dealer tells me I need to replace the wiring harness because of 'rubbing' - but I see you taped yours up. That's exactly what I'd like to try first - but not exactly sure where to look. You mentioned right behind the intake manifold - not quite sure where I'm looking.

Hope you can help - and save me $300!!

Thanks,
Dave

Re: (davidcharlie)
 

I just had the same prolem happen today:

Eratic speedometer
check engine light came on
clunky performance ( feels like it's going to stall )

I'm going to do the following tomorrow:

Voltage check on battery
body to engine ground
check alternator

Should I do anything else?

Paul
1997 Civic

Re: Help! Erratic speedometer and headlight dimming issue
 

Did any of you ever solve this problem? We are having the same issue with our 1998 civic dx. already replaced the alternator to no effect. Found a couple of wires we taped up, still no fix.

Re: Help! Erratic speedometer and headlight dimming issue
 

Same symptoms. I replaced the alternator but problem persisted. I will look for a grounding/shorting problem as suggested by ccjustin. That also explains the check engine light and the code it throws.

Thanks for the information.

Re: Help! Erratic speedometer and headlight dimming issue
 

alternator has nothing to do with an eratic speedo, it is definitely the SPEED SENSOR located on the transmission (it is located near the FIREWALL). Normally CHECK ENGINE will appear if this sensor starts going out. Headlight issue will definitely come from poor power supply such as the alternator or battery. Good luck on the fix!

Re: Help! Erratic speedometer and headlight dimming issue
 

yep i Had this EXACTTTTTT issue.

It was a bad alternator.

n form time to time i see cars the the lights dim n speedo/rpm goes crazy,it was a bad connection to the battery. cleaned the terminals n good to go!!

Re: Help! Erratic speedometer and headlight dimming issue
 

We checked the ground near the headlight, cleaned it, it is fine. so the car has a new battery, a new alternator, and the wiring harness wires have been inspected and repaired where they were bared. We are going to look into the VSS, but if anyone has other suggestions of where to look for wiring troubles it would be appreciated. Thanks.

Re: Help! Erratic speedometer and headlight dimming issue
 

if you guys will search a bit more you will find the answer. i just answered this in another post yesterday. check the wiring that is next to the IM or behind it. it is suppose to be held on by some metal clip, either that clip corroded through the wire and it is shortening the wire check that area as it will solve your problem...

Re: Help! Erratic speedometer and headlight dimming issue
 

maybe the speedo... how ever you are wrong about the alt

bingo, our cars rely heavily on having enough electricity to do everything... so a bad battery connection or even an alt can most definitely cause this

Re: Help! Erratic speedometer and headlight dimming issue
 

I have checked out the alt & battery & wiring behind the IM which was grounding out now repaired also checked one grd in engine compartment still having an issue. I will check all the other suggested problem spots.

Re: Help! Erratic speedometer and headlight dimming issue
 

Fuse 15 was blown. We replaced it and everything is working now. Hopefully that was it.

Re: Help! Erratic speedometer and headlight dimming issue
 

I agree with ccjustin. Sounds like the common short circuit problem of 6th generation Civics. If fuse 15 blows again, carefully read this TSB.

Re: Help! Erratic speedometer and headlight dimming issue
 

its usaually the ELD fuse (electronic load detector) it will feel like its gooin to stall and the speedo, rpms and lights will go nuts. lol. hope this helps

Re: Help! Erratic speedometer and headlight dimming issue
 

If you have erratic speedo, blown fuse #15, pulsing lights, rough idle, random shifting but alternator is OK, see post by RonJ@HT Jan 31, 2009. My car had exactly what his attachment addresses - a wire rubbing on a support bracket and shorting out. This is obviously a design oversight. Thanks for everyones input which gave me clues what to look for.

Re: Help! Erratic speedometer and headlight dimming issue
 

mines did the same thing.. i added another ground and BAMM!!! everything worked fine again.. hopefully it does the same to you ^^

Re: Help! Erratic speedometer and headlight dimming issue
 

alternator..gl