DASH WARNING LIGHTS INOP ---->TRIM REMOVED!!!<----

TurboRay · Post by **TurboRay** » 05 Jan 2007, 15:15

Howdy, y'all - Noob here.......SORRY for the long post!

Recently, about 85% of my dash warning lights stopped working (along the lower edge of the cluster) and the alternator stopped charging. Thinking that the problem was with the (Nippondenso) alternator, I replaced it - but, that didn't help. I then discovered that the small "exciter" (??) wire that plugs into the alt had no voltage with the key on. Apparently, this wire gets its current THRU the charge indicator bulb. Sooooooo..................the charging system prob seems to be a result of the inop warning lights and not the other way around!!

In trying to determine the prob with the warning lights, I discovered that they momentarily come on when I reach under the dash and apply pressure to the back side of the cluster. Therefore, I ASSume that there's a bad connection, either power or ground - OR, a prob with the printed circuit.

Unfortunately, however I can't figure out how to remove the (Yazaki) cluster in order to check it out. My cluster is (for lack of better descriptive terms) shaped like a trapezoid. In other words, it's not like the rectangular clusters I've seen depicted in all the Chilton and Alldata "manuals" - mine has 45

Post by **billofdurham** » 05 Jan 2007, 16:59

There is a plastic cover panel at each bottom corner of the instrument cluster. Pop these out with a small screwdriver to expose the retaining screws.

Bill.

TurboRay · Post by **TurboRay** » 06 Jan 2007, 02:07

THANX for the response, Bill! Unfortunately, however, those little "cover panels" you refer to are apparently only present on the models with the rectangular clusters, such as those depicted in my Alldata program and the Chilton manuals I've looked at in the local library.

My 740 has a different style of cluster with relatively-long 45

Post by **MadeInJapan** » 06 Jan 2007, 07:29

This is an image off of ebay:

So yours must look like the above picture. Looking at the clasps on the top, it appears that pulling out on the bottom while pushing in on the top might do it or vice versa. At least this picture might help in some way.
Also came across this. Couldn't find directions but maybe this diagram will help:

Good luck and I hope you get it figured out.

TurboRay · Post by **TurboRay** » 06 Jan 2007, 09:53

Yes, MIJ - that's my dash. THANX for the response and especially the pix! The trim piece that I'm trying to remove for access to the cluster-retaining screws is designated "21" in the exploded view you posted. I have removed the lower switch plates that reside on either side of the steering column in order to reach in and remove the two black "clips" (22) that are depicted and also shown at the bottom of the cluster in the eBay photo.

I'll try the "pulling on the bottom/pushing on the top" (and vice versa) suggestion, along with a few more things before intentionally destroying the trim. I see, in the exploded view, that the offending trim apparently has what appears to be a U-shaped vertically-oriented "slot" molded onto the L/H side (and, perhaps on the right as well) - so, I'll try vigorously pushing the trim down, one side at a time, while attempting to pull it out of engagement with whatever "pin" might fit into that/those slot(s). But, other than that, I've pretty much exhausted just about every trick I can think of with no success.

As a 7,700+ count poster on turboford.net, I know how much effort it takes to look up the info, photos and parts breakdowns and then post 'em to the topic. So, I'm extremely grateful for your help. guys - THANX again!!

C'ya - RAY

LaRy · Post by **LaRy** » 06 Jan 2007, 12:35

I would say that you are maybe on the wrong track. That small exciter at the alternator should have no voltage from the charging bulb. The principle for the charging bulb is that from beginning with not charging alternator you have +12VDC from one sida at the bulb. Because the alternator is not charging the side connected to the alternator is connected to ground through the windings in the alternator. When the alternator starts to charge, this small exciter should get +12v because charging in the alternator winding. Now the charging bulb will get +12 volt from both sides, and the warning light will go out.
If you turn the ignition switch to drive position, all warning lights should turn on to indicate that all bulbs are OK ( according to regulations in some contries). If not, the connection (ground) through the alternator is bad. I've met the problem that the thin wire is broken because of vibrations, very close to the alternator.

TurboRay · Post by **TurboRay** » 06 Jan 2007, 13:08

Well, I'm certainly not here to argue with the Volvo experts, LaRy - but, as an ASE-certified "master mechanic" with just over 40 years in the biz, it's been my experience that the alt needs to be "excited" with a minute current being applied to the rotor winding. In the "old days", for instance, before alternators began to appear on domestic cars in the early 60's, generators needed to be polarized (field shoes permanently magnetized) in order to create that small amount of magnetic flux necessary to initiate charging.

With this Nippondenso alternator and most others that I'm aware of, current has to come from the ignition switch in order to magnetize the poles of the rotor to initiate charging. When I jumper between this alternators main output terminal (battery voltage) and the small connector, the alternator begins charging and continues to charge even after removing the jumper. It also begins charging when I press on the back of the instrument cluster and the warning lights pop on.

My understanding of the circuit is virtually the same as yours - that the small alt connector is grounded thru the alternators slip rings, rotor winding and ultimately to the chassis when it's "at rest"/key off. Then, when the key is turned to the "on" position, battery voltage is supplied to one side of the charge-indicator lamp and passes thru the filament and on to the small terminal of the alt. The lamp is illuminated because this current is grounded thru the rotor winding of the alternator..........UNTIL it starts charging (as a RESULT of the magnetism caused by this miniscule amount of current) - at which point 12+ volts becomes present at both sides of the bulbs filament and it goes out.

C'ya - RAY

TurboRay · Post by **TurboRay** » 09 Jan 2007, 00:44

SUCCESS!!! (SORTA)

Turns out that the trim piece I've been trying to remove is actually made of black-painted (pot)metal and not plastic, as I originally thought - dohhh!

I was finally able to apply enough force to remove it, whereupon I partially broke the mounting for one of two spring clips that retain it (AAAAAARGH - but, at least it won't show after reassembly). After examining the retention method, I've discovered the way I SHOULD have removed it.

Ideally, the correct removal tool would probably resemble something like a long #1 Phillips screwdriver with about 1-inch of the end bent 90

Post by **billofdurham** » 09 Jan 2007, 11:25

Oh well, I guess the majority of y'all don't hang out here in the RWD section, eh?

Unfortunately RWD are becoming as rare as hen's teeth. I, for one, regret that as I much prefer RWD as some amazing driving can be done in them. I am now on the lookout for another 960, but good examples are hard to find in the UK.

Back to the topic:- Good to see you got that trim off. I still can't find that instrument cluster in any of my books.

Keep us posted on the end result with the dash lights, it may help someone else in the future. It will also let you post another one in this thread!

Bill.