2001 S80 burns out headlights constantly

dtropnevad05 · Post by **dtropnevad05** » 28 May 2014, 17:28

So we have had this S-80 for about 4 years now and have replaced the headlights 6 times! I just put yet another new set in today.

I noticed the inside part of the headlamp moves around. The reflector lens where the bulb attaches. The right side is tight and has no movement at all. I also checked the voltage at the sockets and found it to be 14.2-14.4 volts with the car running. I did notice that the spade connectors seemed a little lose so I bent then in a little and they now are very tight on the bulb.

About 8 months agoI had taken the headlamps out when the car was in the body shop. To clean the inside and remove the moisture that has been in them since we bought the car. When I put the glass cover back on the rear of the headlamp assembly I added a small bead of high quality silicone caulk in the center of the indent of the gasket. Then reinstalled the stainless steel clips around the headlamp assembly. I also bought new o-rings for the back round cover to help keep any water from getting in behind them. The headlamps have not had any moisture since then

.

I have tried Volvo bulbs, Sylvania both the Silverstar and Silverstar Ultra but they all last about the same. So any ideas as to why this is happening, the local dealer said to bring it in and they will check it out, with an estimate of one hour to up to 3 or 4 hours

!

Any ideas as to what could be burning these bulbs out? Anyone else having the same issue with their Volvo? Any help would be greatly appreciated guys!

Thanks Don

Post by **jimmy57** » 28 May 2014, 21:27

My suspicion would be your voltage regulator is overcharging at times.
2000-2001 S80's have a high failure rate for those. Has the car been checked for full car system codes? You may find overvoltage codes. You can NOT have those codes with this problem but still see short bulb life with no other issues.

Get one of the cheap cig light volt meters and watch it for a time and see if it isn't going to 15.4V or even higher for periods of time.

The 14.2-14.4 is bit high idling if the lights and blower are on and the engine has been running long enough to have normal underhood temp.

If it is all normal then you can splice 2 feet of 18 gauge wire into the low beam feed for both side low beams. That smaller wire will add a voltage drop that will lower the voltage enough to lengthen bulb life. Volvo made adapter harnesses for this very purpose for some models but they are $100 range for two. You can splice the wire in and get the results for less than $10. Starting with 2005 model year all volvos have voltage limited lighting circuits. The bulbs now are supplied with no more than 13 Volts.
The hour life rating of automotive bulbs plummets above 14V.

Post by **precopster** » 29 May 2014, 07:54

The regulator should be a FOOM145229 which is easily replaceable. You will get 14.25 with a new regulator and no load (lights off)

With an older regulator with say 160 k miles expect around 13.3-13.8 volts with no load and less with lights on.

dtropnevad05 · Post by **dtropnevad05** » 29 May 2014, 09:27

OK Thanks guys, I will replace the voltage regulator and go from there. The dealer here in town wants $140 US just to read the codes

. I have a code reader but it is not the Volvo system. So for $40 I can buy a Bosch regulator and even the OEM wiring harness for the same cost the dealer wants just to read the codes for me!

The bulbs do look like they were over loaded as the filament looked like it had exploded with pieces of it melted to the inside of the glass. That was why I looked at the voltage, as I posted it was between 14.2 & 14.4 with the headlights on but nothing else, the car was up to temp also. Jimmy do you happen to have the number for that harness?

Again THANKS for the very quick response guys, that is what makes a forum great

Don

Post by **jimmy57** » 29 May 2014, 10:30

I do not have the part number and the part was limited time and would be withdrawn now I would think.
The harness was not anything special. It was just easy. It had a male and female plug with three or four wires depending on model and the low beam wire was 2 feet of small gauge wire zigzag folded and taped. The wire was not resistance wire. Small gauge wire carrying the bulb current load had a voltage drop level that served the purpose but it didn't get too hot. The lights may be a bit less bright but usually the light output experiences diminished returns for voltage above 13 V.

Eliminate the V regulator first. Lots of 99-04 S80's with normal headlight life out there when the voltage is within normal range.

matt5112 · Post by **matt5112** » 03 Jun 2014, 18:49

Just a heads up, the brighter bulbs have significantly shorter life spans.

They're rated at 12.8 V instead of 13.2V for the same wattage. This means they use more than the rated wattage at higher voltages, burning them out very quickly. I'd also be leary of this because of the interesting headlight shunt system Volvo built around the CEM.

VolvoOregon · Post by **VolvoOregon** » 06 Oct 2019, 15:44

Hi, Did you ever figure out the VOLVO S80 headlight bulb burnout issue. I’m replacing my left bulb every other month.

Thanks, Jim Small in Portland, Oregon