2000 S70 Lighting pulse and front end vibration.

Philco456 · Post by **Philco456** » 06 Nov 2003, 19:51

Two problems - both very annoying. The first is a light pulse only when the vehicle is running. All lights (interior and exterior) continuously brighten and darken slightly as the car is running. This occurs very rapidly and it seems like the power supply is alway changing strength. The second problem is a vibration in the steering wheel around 55 mph and again over 70. The wheels are perfectly balanced. I have noticed a loud thud when turning the wheel sharply to park in a parking lot and when the car rocks left and right going over bumps at slow speeds. Could this be related? Any ideas?

ddo · Post by **ddo** » 12 Dec 2003, 04:55

Hello,
I have a 1999 (august) V70 and have the problems concerning flickering lights too. I measured with an oscilloscop and I found large currents in the oxygen sensor heatings. They have a resistance about 1.6 Ohms at the front sensor and 6 Ohms at the rear sensor. The current is about 10 ampere at 14volts and therefore the bord voltage is breaking continously down to the battery level.

I heard it from seperate people too, they all have denso electronic (ECU).
Which system do you have?

Have you the flicker problems all the time or does it go away with a hot engine?

Bye, Daniel (germany)

Philco456 · Post by **Philco456** » 12 Dec 2003, 08:58

Hey,
Thanks for the info. Did you ever have the problem corrected and if so, what did you do? I have no idea what electrical system I have. I was thinking that it was just the voltage regulator - I suppose I should just take it to the dealer to have it checked out. It seems that the lights flicker a bit more when the car is cold, but it does it all the time - cold or hot.

Post by **matthew1** » 12 Dec 2003, 10:26

The second problem is a vibration in the steering wheel around 55 mph and again over 70. The wheels are perfectly balanced.

Sometimes balancing cannot make up for out-of-round wheels. I've even heard of someone buying new wheels that were afflicted with this syndrome. The dealer took them back on exchange for round ones.

Post by **matthew1** » 12 Dec 2003, 10:28

Change "wheels" to "tires" above.

.

ddo · Post by **ddo** » 17 Dec 2003, 05:13

Hi,
I replaced the voltage regulator but it took no effect.
Replacing the alternator as the second step (guarantee up to april next year

) took no effect, too.
Therefore the pulse-switched heating and other pulsed actuators seems to be the cause...
All you can do is to apply a capacitor to the dashlight-supply, to make the supply voltage for these things more smooth.
Until now I did nothing, but I wonder what Volvo did there!?!

You can check the electronic (whether DENSO or BOSCH) while looking at the engine, I believe to remember that at the timingbelt housing is a sticker with infos. The second way is to clips off the top of the ECU-Box at the right side (LHD-models) and look at the sticker there. I am anxious to know which brand do you have!

Greetings, Daniel