Silly question. If the OD light does not come on when the switch is pressed does that mean that the transmission is always in OD? Also, I don't feel the tranny downshift when pressing the switch.

In these days of expensive gas I just want to make sure that the OD on my vehicle is engaging when it needs to.

It is my understanding that pushing the OD switch normally turns your OD off?
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1992 240GL, 1992 240DL, 1985 240DL Wagon, 1983 240DL

Thanks for your responses.

However, I already swapped relays between my 92DL & 92GL and still no light. Got under vehicle and checked wiring going to solenoid- looks ok.

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1992 240GL, 1992 240DL, 1985 240DL Wagon, 1983 240DL

0) Did you check the fuse?

1) Did you check if it's shifting in + out of OD but light is not working? (dead bulb)

2) If not shifting in + out of OD, did you find wire going into tranny tunnel from front of shifter housing box? It drops down around the driveshaft to the right, then goes forward along right side of tranny for a ways.

The wire often breaks where it passes the driveshaft, at a u-joint. My guess is that it blows around a bit in the breeze and gets whacked by the driveshaft now and then. Eventually it breaks.
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors, quad horns, tach, small clock. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Thanks to all. Determined it is just bulb that is out
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1992 240GL, 1992 240DL, 1985 240DL Wagon, 1983 240DL

Auto transmission, correct?
If yours is a standard then the below might not apply.

Normal operation is that OD is enabled when car is started.
Enabled meaning that it will go into OD if speed and throttle position are appropriate for OD. Usually somewhere above 40-45 mph.

You should feel OD go in and out when you work the button. Should be noticeable when cruising between 45 or 50 mph and about 70. Also if you can moderately accelerate from a dead stop to about 60 you should feel it shift three times, to get to OD.

If you feel it shift in + out of OD then it's just a dead bulb. Fixable as B.C. wrote.

If not, first check that the fuse isn't blown. Sometimes they get corrosion so also roll the fuse within the holder to cut through any corrosion.

If still not working and fuse is good, the OD relay could be bad. If fuse blows as soon as you replace it, likely a frayed wire in the transmission tunnel just below the shifter lever housing. Frayed or torn wire can also disable the OD without blowing the fuse, but I believe the indicator light would work in that case.

Relay replacement is doable with a phillips screwdriver and no experience. Part is maybe $25-35 or so. Repair of frayed or torn wire is a moderate PITA but doable in a driveway if you have jack stands or similar.

Post back. If needed we'll give pointers on replacing the relay or repairng the wire.
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors, quad horns, tach, small clock. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Not so silly, and besides, them may be others with the same Q.

In general, your premise is correct. No light = O/D is not inhibited so the tranny will shift when throttle position and speed warrant it.

Do you have a tachometer? From the day that I got a Volvo that came with one, I have retrofitted every one since. Easy to do, signal wire is factory.

The O/D on the anuto tranny is about 20%. Means that if the engine is running at 2500 rpm in 3rd, shifting to O/D will keep the road speed constant but drop the engine speed by 20% or 500, down to 2000 rpm. Best to do this at 45 on a level road, higher speed on hilly terrain. Below 35 or so the o/d won't engage.

Test on the highway. Hit the gas kinda hard and feel the shifts. 1->2 happens pretty quick, then 2->3 is quite noticeable, and 3->o/d is, too.

The indicator bulb CAN burn out. BTDT On my older 240s, w/o air bags, it was easy to pull the knee pad, lie down with the pedals and reach up in there to pull the o/d bulb and swap in one from a nearby non-used light, like the one for o/d in a manual tranny car, it's a green light.

The bulb can be dead and the solenoid and relay still work OK.

Good Luck,

Bob

:>)