'97 V90 Rear lights, madness

[Faust]

OK, this is the otherwise excellent V90 I bought the other day,.

When the main lights are off, the directional "appear" to operate normally when watching the dash lights. In point of fact, when the right directional is on, the right rear back up light flashes.

When I turn the main lights on (headlights, or parking) The directionals cease to operate at all and the right rear back up light comes on. On the dash the right directional arrow remains lit, but does not flash,.

I have pulled down a wiring diagram from the net. the color codes shown for the wires seem only "similar".

At the tail lamp the wires "pretty much" match the color code tags on the taillight unit.

I am wondering if he taillight unit is from a 960 and for some reason varies.

Never having mastered electricity, I am at wits end and cannot pass inspection,.

Any help,, or suggestion, much appreciated.

[lummert]

There was a bulb-out relay for the rear lights in the left rear of my 1988 765. I'd think maybe your car has the same relay. I had to bypass this relay on my 765 as it was causing the right tail light fuse to blow. The wagon tail lights should be interchangeable from 740/760/940/960/V90 (even though later tail lights had clear turn signals). Did you have the tail lights out for some reason? Maybe double check that they're wired correctly.

[Faust]

Thanks for the reply.
"There was a bulb-out relay for the rear lights in the left rear of my 1988 765. I'd think maybe your car has the same relay. I had to bypass this relay on my 765 as it was causing the right tail light fuse to blow."

I didn't see anything I would recognize as a relay, but I notice what appears to be a fuse in the left rear, hard by the tail lamp. Now that you mention it, I get a "bulb out" light on the dash when I turn the parking/headlights on. This disappears if the lights are not on.

"The wagon tail lights should be interchangeable from 740/760/940/960/V90 (even though later tail lights had clear turn signals). Did you have the tail lights out for some reason? Maybe double check that they're wired correctly."

I pulled both taillights to check the wiring. As mentioned, the color coding of the wires did not match the wiring diagram I downloaded,. Looking at it now, I note that it is a wiring diagram for a 960, although I selected V90. Is V90 a U.S. only designation? What I really need is a picture of a right hand assembly showing wiring colors., The left hand unit is extraordinarily complicated having what seems like 10-11 terminals.

[lummert]

www.volvowiringdiagrams.com
Volvo 960/S90/V90 (1997-1998) Wiring Diagrams
Listed as S90 V90 Wiring Diagrams
Shows wire color and position on tail lights.

[Faust]

Those are the wiring diagrams I pulled down before. The color codes on the diagram do not match accurately with my car. The color codes on the lamp assemblies match the wires better, but not 100%

[jimmy57]

On both of my 1995 960 wagons the problems you list were bad contacts with the galvanized metal plates that make up the conductor strips on tail lamp assemblies. I sanded the metal "fingers" on bulb sockets, steel wooled the galvanized and used some grease when I put the bulb sockets back in to try to keep corrosion at bay. They worked till I got rid of both cars.

The bulbs lose the ground and then the tail light do odd combinations of lighting via grounding through the filaments of othr bulbs.
I could turn on taillight and hazard flashers and prop something between seat and brake pedal to keep brake lights on. Then I would use a long screw driver and push on the contact fingers of bulb sockets with the access cover popped off. The lights worked correctly if I pushed on the ground finger against the galvanized plates.

[Faust]

Jimmy57 - You got it!

I discovered that was my problem about an hour ago, I had been disturbed by those conductor strips and what they might be doing. So, I scratched the offending contacts with my pocket knife and got light. Will pick some dielectric grease and dremel tool (from my "sheltered workshop" which is on the other side of town. When I go off my meds, I go there and play with my insane hobbies)and do all the contacts. Thanks for your reply. Never could coordinate those color codes ,.

[Faust]

I spake too soon. I now have my directionals back,. but I still lose them as soon as I turn on the parking lights, or headlights.. With the headlights on, I get a right turn arrow on the dash, but it is steady and doesn't blink,. Based on other posts here, I will begin pulling fuses until I find the circuit which seems to cause the problem,. I intuit that a likely cause is a bad ground,.

[jimmy57]

Before you go too far take an alligator clip lead and attach to the bulb socket for taillight on what you can ID as ground. The power feed wires are very near each socket but the ground is only attached in one place for that grd strip. the current is going through filaments of non powered bulbs to ground. That turns on the indicators dimly.

[Faust]

Here is the latest,. I have the rear directional working, the brake lights work,. When I turn on the parking/headlights, the right rear directional comes on and stays on, does not blink (either side) regardless of the turn indicator position lever,. At wit's end,.