1998 v70xc head light upgrade

1998v70xcbill · Post by **1998v70xcbill** » 04 May 2014, 17:31

I've had my first volvo for 2 months now. Bought for $1900 at 190k and a lot to fix.
Decided to change my high beam bulbs for the low beam bulbs. I figured the high beam bulbs had to have lower hours on them than the low beams. They did, the high beam bulbs looked new and the low beam bulbs looked used. So i swapped the high beam bulbs for the low beam. I also know that i always have a spare low beam bulb, buy using a high beam.

Found out that the driver's side head light reflector was loose. Had to remove headlight assembly from car, and unclip glass lens to fix. Easy fix, Then I had to reline the head lights.

I then checked the head light wiring for voltage drops. Meter between + bat and + low beam with engine off showed a voltage of 0.8v (low beams on). Meter between - bat and - low beam was 0.2v .

I then checked voltage drop from fuses 21, 22 to the + low beam. It showed the voltage drop was mostly in the wiring and not the relays or switches. There is just wire from the fuses to the light and it showed about 0.6v .

I noticed a wiring jumper (4" plug to plug) connected to the head lights. I wondered what the jumper was for. I removed both jumpers, clean plug contacts at head light, and cleaned a ground connection below the ignition coil. The 0.8v went to 0.47v, I was happy with that. I know that about 0.2 volts is due to the relays and stuff, so 0.27 was left for the wiring (POS).

0.2v drop for the negative side, i think can be improved, so i will make a direct ground connection to the negative side of the bulb.

Found out later, volvo added the wire jumper to add a voltage drop to extend bulb life. So do yourself a favor and remove the jumper a turn off day time driving lights.

I can't believe Volvo added resistance to the wiring on purpose! (as a recall)

Bill

1998v70xcbill · Post by **1998v70xcbill** » 04 May 2014, 18:25

can some one please tell what years had this crazey recall jumpers.

Post by **Ozark Lee** » 04 May 2014, 18:34

As far as I know it was just the '98. The original harness on the '98 70 series has a nasty habit of burning up.

Getting the old harness out is a bit of a challenge if you don't remove the whole headlight assembly due to the location of the locking tabs. I have used a cutoff wheel on a Dremel tool to carve the old one out and once the old one is out the new harness assembly snaps right in.

...Lee