instriment light switch replacement?
 

o my god it looked so easy in the manual... its NOT :eek:

I'm having "issues" removing the instriment cluster, to replace the instriment lighting dimmer... god help me, but i DONT KNOW what i did wrong...

"remove the lower dash panal and reach up and push it out"... i cannot remove the G/D PANAL... I undid all the screws holding it in place, and pulled on the inner lower edge, and it "wiggles" but insted of just the dash panal wiggeling, its the dash pad, and the wooden part with all the a/c vents and e-break releace and everything...


Can somebody help me? I'd really appreciate it... car is a 75 300d (i ALLWAYS thought it was a 76, but its inshured as a 75... great huh?)

Thank you very much
~Nathan

Sounds like you've loosened the whole dashboard. Now, put those bolts/screws back in.
I think 'lower dash panel', means the cardboard cover under the dash. If yours is still there, it's usually secured under the dash with some small grey press-in button clips, and at the firewall with some screws/bolts at the steering column. If your cardboard cover is free or missing, you should be able to reach up through/around the steering column/handbrake area and push the instrument cluster loose from behind. Sometimes the rubber gasket securing the cluster to the dash shrinks with time and you may be able to simply work the cluster loose by gently tugging on the rheostat knob or odometer reset knob.

Happy Motoring, Mark

i hate my manual... i really do... It ABSOLUTLY shows the "lower dash panal" as what i removed last night... remind me to burn it sometime...

OK at 3am last night, i has a stroke of luck (been out there 3 hours allready...) and rememberd that it said to "remove the lower dash panal" and push it out...

I wrapped a large flat screwdriver with a rag, and gently pried it out... then batteled with the spedo cable to get it out... so after it was about 3 inches out of the dash, i removed the switch and then realized the problem...

in the 30 years it had been around, the spring "fell" out of the slot its in, and the rider? only touched it in a few areas...

being as a new one was $75, i sorta rebuilt it, and improved it... I cleaned the contacts with a grinder (very carefully) and the ther one i scratched the crap off with a scrach awl, then cleaned it with a pencil eraser... Then put a dab of glue in the slot, spread the spring out, and pushed it into the slot...

And then it went back in, and i fought the spedo cable AGAIN for at least 30 min... hooked that back up finally, and then realized my preglow light wasnt commign on... i finally said screw it, i gotta get some sleep (time is now 5:30)

And now i realized that light just came out... pushed it back in, and it works, along with the dimmer...

Now i just gotta replace the lights (dont need to replace them all... but ones shot, and theyre cheap anyways...)

remind me to contact hayes and tell them their manual sucks, and inform them where they can stick it...

(i also tried the cardboard panal... all the wires and a/c is there... cant get at it at all)

It's all back together, and everything works as it should, except the spedo (havent taken it for a test drive yet, but is should...)

thanks alot
~Nate

I am having more or less the same problem, the cluster is loose but it doesnt come more than an inch out, so i cant reach the speedo cable. Do you have to remove the cable from under the dash?

On the 250C, there's also the oil pressure line and temperature guage line to be carefull of. As for the speedometer cable, look to see if there is a metal strap or clamp securing it to the footwell, by the pedals or steering column, that can be loosened. Otherwise, you may need to disconnect the cable at the transmission to get enough slack to pull the cluster further.

Happy Motoring, Mark

Cluster removal
 

Over years of doing this in several W114's, have usually found it easiest to pull both the oil line and the wiring connector, in order to permit easiest access to speedo cable with left hand (on a LH drive) from under and behind (unless you have a very small gnome you can send in to do same job, or plenty of slack cable).
Please do, if repairing the rheostat, remember that the wire coil is a resistor which gets hot - pay attention to flammability of your cement, if used (there's a couple of reasons it's mounted in ceramic). Max resistance and total heat is direction in which you have most dimming - may be worth "live fire" (so to speak) testing with lower panels still out and CO2 fire extinguisher handy...
Happy paneling!

could be the wireing plug too. i think i had to monkey with that from below. be careful not to split it open.. there are a number of wires and it took me a few hours to figure what went where..

Just solder the contacts together with a wire and have full on. I can't see using it any other way then full on anyway.

lol. mine are a bit dim also..

Will do as soon as I can get the cluster out ;)

BTW, the chrome rings on the cluster are a bit loose, anyone know how to fit them properly?

i used tiny bit of contact cement.

well i think all i have on my dash is a clock knob and a trip meter- where is the dimmer?

thanks- Mo

dimmer is the little knob that's just like the trip meter reset.

knob clarification
 

Mo-

The dimmer knob IS the (left) odo reset button - when pushed, it engages a little arm which resets the odometer; when rotated, it turns the rheostat which consists of a spring contact arm which rotates and rides along a coiled resistor wire mounted in ceramic, thereby passing current through more or less resistor enroute to light circuits, including, in the 114's and 123's, some sites served via fiberoptic "lines" which transmit light from pea bulbs in little holders.