I am a newbie and just got my 1990 Volvo 240DL. I was reading several threads on here about the overdrive not working (light on) and I think the consensus was that the overdrive relay is likely bad. I went through the service records that I got from the previous owner and evidently the dealer diagnosed the problem as the relay. SO, I bought a new one on ebay. Now, I need to put this is. you have to remove the glove box, correct? Is it just a matter of taking all of the screws around the perimeter out and removing the box. One I get that out, I assume I look for the white relay. Do i just pull the old one out and insert the new one?

Thanks for all the help.

Don
1990 240DL 136K

Exactly. Its behind the center vents.

Awesome! Thank you. 70 mph on the highway without OD is pretty loud, so I am looking forward to having OD.

U didn't read this common post


OD light on === OD IMpossible;

OD light OFF=== OD possible!

Default is light OFF

IE it might be working, but you've got the light arse-about!

Like Many b4 U.

Well I fixed it. I bought an OD relay on ebay for $13 and put it in last night. It fixed the problem. The light is out and you can feel it go into OD. Hooray! Much nicer ride at 60 mph in OD, instead of 3rd.

DAMN! The OD is back to not working. The light is on and it is not going into overdrive. It worked for a few days with the EBAY part, now it is not working. When I first get in the car, the light is on and i press the switch and I can hear the relay click, but the light does not go out.

Does it sound like I got a bad relay off ebay?

Could be the relay or the switch.

Remove the relay and run a wire from 15 to 87 locations - OD should be enabled permanently (if no other issues) ...

You aren't listening!

LIGHT OFF for OD to work!!!!!!!!!!!!

How many more times do I HAVE to tell you?

:lol:

Who are you talking to? Me? I know that the light must be OFF for OD to work. That is what i am saying. The light is ON and therefore the OD is not working.

Sorry, didn't understand. you mean light permanently on? if so-yep==fault. NB relay is a standard 4 pin with a doubled output, and switched via a bi-stable flip-flop using a 555 timer chip or similar. You can make up a suitable DIY one to replace it if you can't afford OEM new. Copmmon problems with the OEM include cracking internal circuit boards and bad soldered joints. Opening one up and checking is pretty easy with 2 very fine screwdrivers and inspection by holding it up against a light source (NOT the sun!) to se the cracks in the circuit board is not hard. Also examine the relay contacts to see that they aren't welded together. (discard if so!) If several transistors on the board, instead of a single chip, then one may be burned out to short-but that's possibly because some other component has failed too. Any local heat in components other than the coil is an good indicator of that component having failed. This device is pretty immune to probing fingers, which is not necessarily true of all electronics. Used electronics are NOT recommended because age alone will cause failure, and a used part is already old-so it's failure date is usually much closer than a new part, and it might be today-there is no way of knowing with any certainty, but, 15Yrs is typical reliable life of discrete electronic components in non-commercial use other than transistors and coils, they should last indefinitely. After that - anyones' guess. There aren't many >10yo PC's about, tho' there are a few 20yo TV's/radios around, usually working poorly. These might be a guide as to what to expect. NOS electronics are thus a poor saving, unless you KNOW when it was made!!!!!

I bought another used relay (pressing my luck). It went out in two days, but had a warranty. I got another one. The most recent one was from an 88 740 and i noticed that the plug was made out steel/nickel whereas the previous relays have all had brass plugs. I wonder if that makes a difference.

The new relay works. I drove this weekend 650 miles and it was great. 75 mph on the highway is SO much better with overdrive.

Glad to hear that. It does sound like you are overheating the relays and the internal circuits are breaking. With the AW70 transmission in the 1990 240 you need the white relay
http://www.fcpgroton.com/product-exec/prod...category_id/172
It looks like the 740 and 240 use the same part.
If it happens again maybe the solenoid is getting sticky and drawing a lot of current through the relay.

All of them have been the white relay and the part numbers have been the same. I do agree with you, that if this one only lasts a few weeks, that the solenoid is the likely culprit.

AW70/71 is also used by Toyota in the Cressida (same years) solenoids are expensive, esp used ones
and a bypass plate is avail cheaper from web. The bypass plate should NOT be used if you tow something or carry full payloads. You'll cook something with the heat if you do, unless you keep your speed below changeover into 4th. That is NOT a guarrantee, just a good, reasoned warning. A sticky solenoid does not draw any more current than a 'normal' one so makes no difference to the relay. relays are a source of failure, and should ONLY be bought new, or carefully repaired. Common probs include cracked circuit boards and bad soldered joits. Burned out circuitry is also common. It's really a simple device, a relay with a bi-stable flip=flop, made from a 555 timer or descrete circuitry. Any self-respecting hobbyist could make one up from cheap generic parts for a lot less than the new relay, or a switch in the dash, and some wires. It's a little difficult to substitute the OEM momentary on switch directly for a lock on switch, but that's really all you need, then you could chuck the relay if you want & go directly to the solenoid. The real purpose of the relay is an expensive but more reliable switch system than a locking switch, until it gets old. A bit like the defiinition of a Harley: An expensive way to turn petrol into noise without the disadvantage of horsepower.