Dim headlight-rewire?

beachrights · Post by **beachrights** » 03 Jul 2020, 11:39

So got a 1999 V70 and noticed a dim headlight- replaced bulb same results. Starting testing circuit and I am only getting 11.7v at the connection. Fuse tests at correct voltage so I assumed a bad ground. tested ground by running additional ground wire from connection to bolt...same results

Then JUST connected power connector to bulb and ran ground straight from battery to ground on bulb to eliminate cars ground wiring and still same results.

Tested switch and 12v all around.

Soooo this tells me I am losing power somewhere along the line right?

Thinking I can rewire headlight circuit using relay for this one headlight only and connect to original switch?

beachrights · Post by **beachrights** » 03 Jul 2020, 11:44

Or can I jump wire from fuse to positive on bulb connection and connect ground from bulb connector to chassis?

Post by **misha** » 03 Jul 2020, 14:49

What voltage you have at battery terminals?
You should have 13.8-14.2v at idle with headlights,heater blower 1-3 speed and radio ON.

Post by **scot850** » 03 Jul 2020, 16:06

I maybe misread this, but OP said he has A dim headlight, not both Misha.

Have you checked the condition of the reflector in both lights. At this age, if someone replaced one, it could be the other is original and all the silvering has fallen off. You can easily remove both headlights and remove the glass lenses to compare if the lens silvering is the same. If they are then something weird electrical is going on.

Do your headlights have the small wiring harness addition between the back of the unit and the main harness to them? The internal wiring in the headlights is also prone to degradation so may be pulling the power down.

Neil.

Post by **Eddystone** » 03 Jul 2020, 16:18

scot850 wrote: ↑03 Jul 2020, 16:06 I maybe misread this, but OP said he has A dim headlight, not both Misha.

Have you checked the condition of the reflector in both lights. At this age, if someone replaced one, it could be the other is original and all the silvering has fallen off. You can easily remove both headlights and remove the glass lenses to compare if the lens silvering is the same. If they are then something weird electrical is going on.

Do your headlights have the small wiring harness addition between the back of the unit and the main harness to them? The internal wiring in the headlights is also prone to degradation so may be pulling the power down.

Neil.

Neil, I'm sure you can help this guy out. When I think of dim bulbs, you immediately come to mind.

Post by **scot850** » 03 Jul 2020, 17:32

Could not agree more!?

Neil.

beachrights · Post by **beachrights** » 03 Jul 2020, 18:27

Scot850 was correct about the reflectors being bad-

When I connected the bulb direct to the battery and the headlight was still dim I was completely lost why still thinking the 11.7v was too low

So lets open up the headlight and see what's doing! Reflector was worn off and housing was yellowish in color.

Saw another post that he used aluminum tape to reline the housing- I happened to have some so gave it a shot and headlight is almost as bright as the good one! Didn't think the tape would help that much! Nice call!

Post by **scot850** » 03 Jul 2020, 19:56

Glad it turned out to be simpler to find the issue. Of course the cost of replacement is high, although if you are willing to use an aftermarket unit or keep an eye out for a good used one then costs can be kept down if the tape idea does not last.

Neil.

Post by **FLXC90** » 04 Jul 2020, 22:08

Now get some "Jewels" From a 2002-2004 C70, and step up. Junkyard or online. The 98-02s are notorious for flaking away.

I wonder if, the water based chrome paint I've seen on some TV shows might work on old reflectors.