98 civic, cel and lights/lamps pulsating
 

Driving to work, the CEL came on. No alt light I guess since I put in a EX cluster with a tach (mine is a DX w/o tach). Anyway, the lights on the dash, radio, heads and tail are pulsatingcontinually when driving or putting foot on the gas to spool up the rpms. All lights just pulsatealmost to the exact beat of the turn signal speed. After shutting off car and restarting, the CEL comes back on and doesn't dim. However it goes back to dimming when I get the rpms up or turn on the headlights. Oh yeah, the speedo goes wacko too. It does all this with the radio, defroster and fan all in the off position and I dont' have an amp either.

Anyone have experience with something similar? I will be checking the battery and alternator with afluke meter after work today and trying to pull the codes. I've never seen a battery or alternator cause a problem like this in all my days. But then again, this is my first foreign car.

Peace!

RE: 98 civic, cel and lights in and out dimming
 

You can pull the CEL code this way:

http://www.honda-tech.com/zerothread/1901557

This type of problem has been described many times on this forum. Do a search. It usually turns out to be caused by electrical shorting of the Vehicle Speed Sensor (VSS) wire harness on the intake manifold. It's possible that you additionally have a faulty alternator, but first try to locate an electrical short.

RE: 98 civic, cel and lights in and out dimming
 

When you have major electrical disturbances you'll often get false ECU codes. So clear up the electrical trouble first, reset the ECU and see if the CEL stays out.

Could be your battery is not securely connected. If you don't have a "battery" light on your cluster it should have a voltmeter instead. Though you can tell from the lights that the voltage is going up and down a lot.

RE: 98 civic, cel and lights in and out dimming
 

Pulled the codes. Got two for the O2 sensors which I'm not really worried about at this point. The other code was unknown and not listed in the scan tool. If I recall correctly it P1298 (wrote it down but left it in the car with the manual). Put a cheap little fluke meter on it and batter was a little over 12.5 with key off. Started the car and volts were down to around 12.1.......reved it up to 2500 and the volts danced around 13.4-14.1 (not what I believe it should be). Checked it with some type of amp meter and it didn't get into the okay section so we assumed alt was bad. Took another hour to get that thing out from the bottom (sure is tight in there) and called napa. As luck would have it, it wasn't in stockbut may be here by Saturday. If not it won't be until Tuesday before it gets here.As luck would also have it, I didn't get it out in time to take it to napa to have it bench tested to ensure that is indeed the problem.I'll get the alt benched tested tomorrow. More later I guess.

Oh yeah. Napa had two alts listed. The standard went for $217, and the premium went for $198. They didn't know the difference. I ordered the premium.Anyone know the difference?

Finally, I've done a little research on code P1298 for the ELD high input voltage. Any chance code came from the alt and/or the regulator inside the alt? Or could there be a ELD problem also that is making everything pulse?

RE: 98 civic, cel and lights in and out dimming
 

In addition to the above, I found this http://autorepair.about.com/library/faqs/bl021d.htm. I don't get the VSS code, but the speedo does jump around. Wonder if it could be this easy. Guess I'll know more after I bench test the alt.

Thoughts?

RE: 98 civic, cel and lights in and out dimming
 

For my 97 Civic, I purchased from AutoZone a replacement rebuilt alternator with a lifetime warranty for $109.

As mentioned by mk378, you should put the CEL codes aside until you figure out the electrical problem. The ELD code is not likely causing the lights to flicker. It is only an energy saving device that turns off the alternator when electrical load is low. Given the speedometer problem and O2 sensor code in conjunction with the flickering lights, the most likely cause of your problems is an electrical short somewhere along the VSS and/or O2 wire harness. If you have not already done so, look carefully for burned or damaged VSS or O2 sensor wires in contact with the engine or manifold. When your repair the short, then replace blown fuse 15, if necessary.

RE: 98 civic, cel and lights in and out dimming
 

guys, i had the same problem with my 98 civic. its a couple of wires under the intake manifold. its kinda hard to see but with a flash light, look under there and it should be a blue harness. take out the negative from the battery first, wrap that around with electric tape. it is also kinda hard to get in there. the reason why you are getting crazy speedometer, pulsing lights and cel is because it is short circuiting. also replace the 15 fuse. and that should solve your problem. i almost went crazy trying to solve that problem, almost wasted alot of money.

pulsing lights
 

my sons civic- pulsing lights, speedo acting like tach, wire rubbed thru under intake brace, also alt fuse will be blown.. cheap fix,, thanks a million..

i have been chasing this problem for two weeks after 2 alts and 1 new battery im gonna go home and check those wires!!! thank you so much for your help:)

Click the Fuse 15 TSB link in my signature for repair instructions.