The amber lights on the Recirc ON and AC off switches flash for about 20 seconds when I start the car (1998 V70 AWD 118,000 miles). My owner's manual says that indicates a fault in the ECC system and that I should take it to an authorized Volvo dealership for service. That, of course, costs a lot of money.

I'm wondering whether there might be something I can do to troubleshoot the system. For example, I could, myself, recharge the AC with R-134a (or whatever), but I don't want to do that if it is obviously not a part of the problem. Any suggestions are, as always, appreciated. Thanks

My bet is that the temp sensor is full of dust and the tiny fan stopped working. The temp sensor is just to the left of the ECC and radio. You could try a vacuum cleaner nozzle on the small grill.

Or, pull out the ECC unit and set it aside. Then reach behind the dash, grabbing the round plastic tube. Pinch the plastic tabs at 12 and 6 o'clock at the grill end and carefully pull it straight back. You need to be very careful with the temp probe which can be easily dammaged.
Once out of the dash, use a toothpick or Qtip and remove all of the dust and dirt from the fan. Put it all back together and the blinking lights should go away.

Klaus
--
Common sense trumps a PhD

Klaus,

Is there a trick to getting the temp sensor out? I tried vacuuming and I thought it had worked, but the little lights started flashing again the third time I started the car. I was able to remove the radio and the ECC unit (thanks for the pointers), but I cannot seem to figure out the sensor. You mentioned plastic tabs at 12 and 6 on the grill end, but I cannot seem to feel them. Are they tiny little things, or should I be able to find them pretty easily. Thanks again.

Small, yes, and they push in towards the barrel. I should have felt around the grill while I was in there to see if it will come out of the dash. It was pretty tightly in place IIRC.
Just try pushing the tabs and wiggle the cylinder up and down slightly while pulling.

Klaus
--
Common sense trumps a PhD

Got it! It seems to have worked. Thanks for all your help!

That small fan does get pretty dirty, doesn't it. Did you manage to get the grill out of the dash, or just the temp sensor out of the rear? It would be nice if the grill came out.

Klaus
--
Common sense trumps a PhD

The fan was filthy. I did NOT manage to get the grill out of the dash, but I did pop out the switches nest to it (TRACS, two dummies, and rear defrost) and that helped with getting a light in there and gaining access.

Thanks again!

Please let the FORUM know if cleaning your temp sensor solves your amber blinking light problem.

Mine also blink occasionally, but I don't think my temp sensor is dirty. However, I do have some intermittent "fluttering" duct dampers, which may cause the amber lights to blink on the ECCU.

The owner's manual only says to have the dealer check the ECCU, if the amber lights continue to blink on successive starts. It does not hint at what might cause such a blink. And nobody in his right mind would go to a dealer with this symptom and hope to escape with his shirt.

Incidentally, EBAY has several "formerly owned" ECCUs for auction and "Buy It Now" at some attractive prices
--
Dave in Virginia; 1998 V70 T5(M): IPD MOTRONIC+ ECU Upgrade, Sport Muffler, IPD Strut Tower Brace; VDO Boost Gauge, IPD Anti-Sway Bars, Rocha ABS Control Unit, Koni FDS Struts and Shocks/// 1988 245 DL Wagon// 1967 MGB Roadster

It seems to have worked. I would have hated to see a bill for this at the dealer. ("Shop supplies"-- 3 Q-tips and some alcohol, would have cost about $10 or so, I imagine).

The ECC units seldom fail, but the other parts have problems. And you are correct re. dealers charging an arm and 2 legs, the engine mechanics hate to work on the vents.

Klaus
--
Common sense trumps a PhD

The E39 model BMW has the same problem. You periodically need to vacuum the little grate to clean out dust. I'll put this on my weekend to-do list.

Wow! Thanks for the response! Is taking out the ECC unit a difficult thing to do? Would you be able to direct me to a site/schematic or some such thing with instructions on how to perform this surgery?

Thanks again!

It is very difficult to take pictures of the backside of the dash!

The ECC unit comes out with a pop, after you take out the radio so you can grab the rear of the ECC and pull. The ECC unit is pressure fitted, no screws. I managed to balance the radio on the shift knob so that I didn't unplug it and resort to finding the code :) As soon as the ECC is out, push the radio back in for safe storage.

Klaus
--
Common sense trumps a PhD

So now comes the next question: Is the radio unit fairly easy to remove? Thanks again!

On both sides of the radio are flush plastic tabs. Push in on one at a time and they will then pull out to reveal a pull handle, then pull :)

Just in case, make sure you have the radio code handy. If you need to unplug the radio or disconnect the battery in the future, the radio code is a must.

The dealer's parts supply person can get you the radio code. You have to supply him the VIN and let him know you are the owner.

Klaus
--
Common sense trumps a PhD