It started out as a simple investigation into why my reverse lights were not working. Once I got the spare tire out of the way so that I could remove the black plastic cover over the driver's tail light wiring, I found a small puddle of water in the bottom of the spare tire well. Then I see this rubber grommet in the bottom of the well that I figured Volvo put there so that it can be removed in just such an occasion to drain this water. I should have known that Volvo engineers think of everything, and as I'm poking around at the grommet I find that a penny (yes, a penny) is in the recess of the grommet. Once I remove the penny, I find that this rubber grommet has a nice little slanted hole molded into it that points toward the rear of the car so that the air flowing under the car will create a draft and help pull the water out of the spare tire well. Oh, the unsung heroes of the Volvo engineering department. Then the more I think about it, I bet the previous owner installed that penny in that grommet because he thought the water was splashing up from the ground. I'm no brain surgeon, but I'm not that stupid. The million dollar question is, "Where is this water in my spare tire well coming from?" Let me tell you....It is dripping out of the bottom of the radio antenna sleeve! Ah ha! But wait there's more. I also find water seeping through an open body seam just under the tail lights. I'll be sealing that up with silicone today. Also found a trim nut missing on one of the molding mounting studs that protrudes into the trunk. That will be easy find at hardware store. I have never torn my trunk apart after having just been out in the rain, but I'm glad I did. I may not have found this in time. A little elbow grease with a wire brush, three coats of rust converter spray, two coats of gray primer, and the spare tire well looks almost new! I recommend that you tear your trunk apart the next rainy day you get. Like me, you may be glad you did.
As for the reverse lights, I had to bend the prongs closer together inside the plug that plugs onto the back of the driver's tail light circuit board.
--
'89 silver 244DL in Milwaukee WI

Keeping water out of a 242/244 trunk seems a never-ending battle to me. Here is Houston we don't get much ice and snow, but we do get lots of rain.

I have semi-permanently installed an old newspaper front section, folded to a long and wide strip, tucked under the lower edge of each tail light and reaching down into the spare tire and RH storage wells.

When it is wet, it gets replaced with another. If it is really drippy wet, more investigation is needed. First, empty the well and dry out. Then pull up the edges of the carpet and check for wet under-padding. That stuff really holds water. If it is wet, the trunk carpet and padding must be removed and hung out to dry. Allow 3 to 4 days.

My leaks, over the years and in various cars, have been though the loose lenses of a tail light. The reverse lens is the only one made to be removed and resealed/replaced. The lower-outer one, brake and tail light in 1986+ sedans, is another problem. Usually a tiny hole in the bottom will suffice for a while.

The way to check is to look into each lamp section through the hole left when the bulb holder is removed. Water penetration, even if dried up, will leave a sort of thin mud on the section bottom. No water = shiny clean.

The only way I have ended this problem in a non-patch manner is this: With the tail light off the car, thoroughly clean the space between the underside of the top row of lenses and the top side of the reflector secions. Then use small-diameter tubing (1/4-inch OD) of some sort to poke into the space and seal it in there with black marine sealant.

If not using new gaskets, I run a bead of sealant around those edges of the tail light unit which contact the gasket so as to get a good seal.

The problem begins, IMHO, with the trunk water run-off design. Water runs off the rear glass and trunk lid into the groove around the trunk seal. The water is canalized in that groove and shoots down the back and splashes onto the top of the tail light, right at the reverse lens. Not many solutions to the water pathway. On occasion I have used a large sheet of plastic, big enough to reach up opnto the roof and held on with a number of magnets - hoping to allow the water to run off without getting into that trough.

Good luck with your reverse light solution. If things get "out" again, try this:

Pull off the connector on the left side. Then open the back side of it, there is a hinge along one long side and tiny catches. Note the location of the reverse (black) wires. One wire brings voltage from the cabin, the other carries it over to the right side. Both touch the wide contact foil on the tail light (same system used on cars with two rear fog lights).

Swap the pincer connectors of the reverse lights. That way the wire from the cabin will touch a foil spot less likely to be burned. I found that this method raised my 1986 244 from zero reverse lights to a left side light.

Thanks for your good ideas and good luck,


Bob

:>)

Great clues to investigate. I get water into the trunks of both my 740s. I'll report back.
Steve

re: "...I also find water seeping through an open body seam just under the tail lights. I'll be sealing that up with silicone today...."

Also consider replacing the taillight's gasket. This is a foam pad (and a better choice than using silicone) that's sandwiched between the taillight and the body panel -- it's supposed to seal that opening (you mentioned, above) against the intrusion of water, and may be the major source of water in your trunk if the "open body seam" is as substantial as you imply.

I know that in my 760, the antenna mast has a small tube running from the bottom of the motor to a small drain nipple. If the 240 motor has this as well, is it possible that the small tube is missing?

My 88/249/47 leaked water into the trunk through the weathered and deteriorated cracks between the separate parts of the plastic tail light. Keep an eye on it as you perform the task of sealing it up. Keep those wheel wells painted up, rust proofed, whatever, because once they go nothing but major body work will seal up trunk. IN fact, the wheel wells are the first place I look when buying a used 240. Good luck.

living in minnesota where the d.o.t. measures the amount of snow, then triples that for salt, tire wells seem to be folklore, except for my new/old 89 245- 206k.i cannot believe that they are intact and sound! wow; i will heed the advice from this post and DEFEND MY TIRE WELLS. carry on my brickboard sons!