When it reached about 10 degrees F. today, my 760t started fine as usual but my dashboard was dark except for both signal light indicators (which were on steadily) and the hi-beam indicator. Gauges and other lights were dead. The signal lights and hi beams were NOT on, just the indicators. When it warmed up, the dash came alive normally. I'm assuming it's a single connection somewhere that needs to be cleaned/tightened, but where should I look to find it?
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87 745T, 97 855. Nine out of ten Black Labs recommend Volvo wagons!

And the ones that care about their appearance prefer the red ones. Golden Retrievers, on the other hand, I've noticed, generally like to ride in green 245s. They set off their color so strikingly.
Bob S.

Looks like this thread went to the dogs!

988

Where is the goung for the light switch.
Rodney

This is a bad connection problem:
I caused exactly the same symptoms on a friend's 88 745, when trying to correct a speedometer problem (which I caused by changing the rear axle.... long story).

With the speedo wiring disconnected from the cluster, you get what you describe. I assume one of the speedo wiring harness wires is a main ground to the cluster. Check that connector- basically center bottom of the cluster. The early cars have a cluster that's surprisingly easy to pull. Screw under the little blank plates at the bottom corners.

Good luck!
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Rob Bareiss, New London CT ::: '87 244DL/M47- 234K, '82 245T/M46-182K, '84 242DL/AW70-100K, '89 244DL/AW70- 212K and I miss my: 86 244DL 215K, 87 244DL 239K, 88 744GLE 233K, 88 244GL 147K, 91 244 183K

Thanks, I'll start looking there! Uh...when it's a little warmer...
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87 745T, 97 855. Nine out of ten Black Labs recommend Volvo wagons!

Do I want to tighten the screws are do I need too put a piece of electrial tape ove r the corner screws. I'm confused on your write up on this problem.
Rodney

I'm having the same problem with a 85/760T. The lights in the dash don't light up and the two indictaor on the top light up. I switched the ignition block and that help the gages but the light's are giving me trouble. I wonder if I got a bad block because it was used. Any body with answers,I hope that you reply.It's cold here we just went down to 13F here on Sunday night.
Rodney

i have never experienced that from the cold, but i did experience the same symptoms when i fried the flexible green circuitboard that wraps around the rear of the instrument cluster. i had a couple of indicator lights on, but they did not go away.
what i can think of is maybe putting some of that dielectric compound there all the lighbulbs contact into that circuitboard, and then unscrew all the screws in the back, and place that dielectric compound on all the screw contact points.
when you do this it is good to NOT place the key in the ignition so the car may be on (thats what i did :0 )and fry the board. this is also a god time to check the main plug for the cluster is on good and tight...and you may as well grease it up too.

this is just an opinion.
9

I would actually advise AGAINST the use of the grease, reason being is its thick enough to insulate the contacts of the lamps and connections enough to create a little heat or at least leave everything in an erratic state. With high voltage ignition its not an issue but at 12 volts a fews ohms drop will really dim a lightbulb.

I would look for bad grounds, pull the connectors, lamp holders and clean them with a wet/dry 600 grit paper and also clean the chassis grounds under the drivers side kick panel and under the dashboard with a 250 grit and tighten the screws good. I had the same issue with mine but it happened not only when cold but when the glow plugs cycled causing my fuel and temp gauges to peg.

I since designed my own LED lighting system for backlighting and indicators using high intensity LEDs and they are not only just as bright but take 1/25'th the current to operate.

988

988, sounds cool; is that something you'd be willing to share the details on? I couldn't design something like that but I can solder pretty well given instructions!

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87 745T, 97 855. Nine out of ten Black Labs recommend Volvo wagons!

Actually it was pretty easy. Good soldering along with a low mass iron such as a Metcal is in order along with 1.5K ohm resistors. Just get some good high brightness LEDs that match the color of the backlit labels and form up the leads to get 1/8" of leg to solder one side down to the foil and cut and form the resistor to fit in line to make the other leg, polarity of the resistor is not important however the LEDs are polarity sensitive... Backwards results in no light. You can use heat shrink to cover one lead if you like but makes no difference really, just adds mass to vibrate. You will need to get an electrical diagram that shows the connection points or you can use your trusty meter to measure. Note Oil, Parking Brake and Brake warn all go LOW to illuminate and the others will go HIGH meaning they are grounded with the low going signals needing a ground to light.
You also might want to stack 4 LEDs in some of the darker places such as the OD indicator. Each position should have 2 LEDs to be effective but I went 4 per hole using T-1 size clear LEDs with 10 degree beam spreads.

Instrument backlighting are high brightness white LEDs wired 4 per leg in series and connected directly to the +12v power source for lighting. You will have to run the cluster on the bench and carefully aim the backlight LEDs to evenly cover the inside of the gauges, direct them through the plastic light guides already in place. Use T-1 size 4000 Mcd white LEDs from Digi-Key (.com) or other supplier, don't buy any of the cheapie LEDs you see at discount prices as they are inconsistant instead get them in a batch from Digi-Key as they are lot matched and made by Panasonic I believe. The dimmer will function as normal however as white LEDs dim they become very blue in color and fall off fast.

Total current draw with all the lights going will be under 500 Ma and no real increase in temprature.

Pretty simple eh?

988

That sounds not too bad, actually. I'll give it a try and let you know how it goes, thanks!
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87 745T, 97 855