1. Home
  2. Volvo automobiles
  3. Day I dread follow up and taillight issue

Day I dread follow up and taillight issue

As I posted earlier, my 86 740 GLE, which I've owned since new, (350k miles) was rear ended. From insurance standpoint, totaled. After much back and forth, got enough to repaint the car (only MAACO), and buy a porta-power to do the body work prior to painting. (And to cover the costs of replacement taillights both sides, which I had on the shelf from an earlier e-bay purchase). About six hours work for son-in-law and I, and we were done. Car is finished, and looks quite nice.

However, the car failed state light inspection (required when reregistering a "totaled" car). The brake-taillights, passenger side, where intermittent. No problem, thinks I. Probably too hasty in my reinstallation following the painting. After 2 hours, I couldn't isolate a ghost ground. The brake lights were grounding through the taillights. After fighting the problem, I threw a diode in the taillight lead, and VIOLA!!, problem solved.

So now Victoria, our 740, will be good for another 350k (or at least outlast our S80!!)>

Reply to
Jim Corey
Loading thread data ...

Maaco paint turned out looking nice? That's a shocker, I've heard nothing but horror stories about them. Paint is one area where I absolutely will not cut corners, a cheap job that turns out crappy or doesn't hold up well will only cost more in the long run to clean up and repaint than using good paint in the first place.

Reply to
James Sweet

Run dedicated ground wires for each light then, if you can... I've looked at the taillights on my 960 maybe twice, and I didn't get a good look at how the power rails were done, but it looked like it was possible from what I can remember... A 960 wagon has the same taillights as a 740, so it should be similar. I remember metal posts, where spade connectors could just plug right into (had to fix the taps for our trailers wiring harness... indicators weren't working, one lead fell off after 11 years) - you might have to cut the common negative rail, if there is one... Check connections, and check for appropriate signals from the positive wires first though, could just be a bad connection. (Check for a constant 12V for the running lights, a flashing 12V for the turn signal, a solid 12V for the brakes, when applied, a solid 12V for the reverse, when in gear, and a solid 12V for the fog lamp/s when on).

Reply to
Rob Guenther

connections,

In a 740 sedan (is this a sedan or a wagon?) the taillights ground with a ground lug stuck on one of the studs that holds the taillights in. Oxidation here is common with an old car, it's certainly possible to ground each light straight to a point on the frame inside the trunk or you can get some of those washers that bite into the metal a bit to improve the connection. The plug and connector where all the wires plug in is a bit of a weak spot too.

Reply to
James Sweet

Those are some good idea's (washers, cleaning the plug connectors).

Reply to
Rob Guenther

Thanks. I actually did the "normal" troubleshooting (i.e. cleaned connections, etc.). I even swapped out the wire membrane on the taillight assembly. After 2 1/2 hours, I took the coward's way out, and did the work-around with the diode.

Thanks for the tips.

Reply to
Jim Corey

Reply to
Rob Guenther

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.