What else is there to the cruise control - PeachParts Mercedes-Benz Forum

retx · #1 02-08-2007, 12:40 PM

My cruise doesnt work. So i removed the amplifier, cleaned the pc and resoldered the entire thing. nothing was burned or shorted, and there seemed to be no cold solder or cracked points. but i did it just in case. well cruise is still not working. what else is there that can be a diy job? no blown fuses by the way. is there any way to check the cruise control actuator? if so, what methods. the fsm has nothing on it that i see. any ideas? thanx

sailor15015 · #2 02-08-2007, 12:45 PM

If no one beats me to it, at home I have bookmarked one heck of a cruise control troubleshooting article. The link is burried somewhere here in the archives but I have it bookmarked at home but I'm at school now.

JimmyL · #3 02-08-2007, 12:51 PM

Where is the cruise amp for a 1980 240D? It has the vac cannister type of cruise unit.

retx · #4 02-08-2007, 12:53 PM

i dont know about a 240.
EDIT: i see in the fsm cd i have that the 240 is the same as the 300. it has an amplifier by the break pedal mount. as well as the actuator on the inside fender. the diagrams for these two look identical.

now that i have found this, does anyone know the number and location of the brake sensor? its raining right now and i havent been able to locate it under the dash and now half my body is soaked.

Surf-n-Turf · #5 02-08-2007, 01:08 PM

Interesting. Might help.
is the brake light Really a problem for the cruise control?

retx · #6 02-08-2007, 01:16 PM

yes ive been watching that. but unless i have a broken ground from brakes back to the cca....this would not be my problem i would think. because my brake lights work fine. although i do have the 1157 bulbs in them. but when i bought the car, no cruise, and it had bosch bulbs in it. one burned out so i replaced them both with 1157.

captainmonk · #7 02-08-2007, 02:59 PM

the sun is out the rain has stopped isnt life grand and retx has cruise

pizzachef · #8 02-10-2007, 03:35 PM

Can someone post what the control lever is supposed to feel like in the different directions?
On mine, I can feel the slight "clicks" in the up and down (accel/set and decel/set) directions, but in the front to back (resume? and off) directions it feels really squishy, and there's no definite click or anything to tell me that the function is being initiated. I've never tested it because I assumed it didn't work. Do you just push the lever up or down? I'll try it today...and if it doesn't work and the lever isn't messed up, I guess I'll pull the amp and see what it looks like on the inside.
Can someone post a link to the tutorial mentioned earlier in this thread. Well, I can probably search and find it..I won't be a slacker

thanks,
-geoff

#9 02-10-2007, 03:41 PM

Quote:

Originally Posted by pizzachef

I guess I'll pull the amp and see what it looks like on the inside.

Careful. If you open it and decide you want it rebuilt, you might be out of luck. The main amp rebuilder wont work with one that's already been opened.

JimmyL · #10 02-10-2007, 08:56 PM

I swapped the cruise amp from the '77 300D into the Squash. Before the swap, nothing would happen via the cruise lever. After swapping, the cruise lever will accelerate the car, and it will hold speed below about 45mph, but only within about 5mph.
At freeway speed it doesn't really work.
It looks like I need to tighten up the cable slack a little bit, which might help with consistency of speed. Also, maybe the extra slack might be keeping it from working at highway speed, as accelerator has linkage moved farther, and maybe too much cable slack to do anything?????
I at least know that the original cruise amp is no good, so may open that one up to see what is going on in there.
I also have an amp out there in Scar. May try that one too....

pizzachef · #11 02-10-2007, 10:12 PM

Quote:

Originally Posted by ForcedInduction

Careful. If you open it and decide you want it rebuilt, you might be out of luck. The main amp rebuilder wont work with one that's already been opened.

Oh, so it isn't recommended to try and fix the amp yourself? If that's the case, I'll leave it alone.

Can anyone help me out with the squishy feel in the control lever? Is that normal for the resume and off directions?
Thanks,
-Geoff

JimmyL · #12 02-10-2007, 10:33 PM

Quote:

Originally Posted by pizzachef

Can anyone help me out with the squishy feel in the control lever? Is that normal for the resume and off directions?
Thanks,
-Geoff

Yes, that is how mine feel.

#13 02-10-2007, 10:40 PM

Quote:

Originally Posted by pizzachef

Oh, so it isn't recommended to try and fix the amp yourself? If that's the case, I'll leave it alone.

Send it here: http://www.gdl-online.com/begin1.html

retx · #14 02-10-2007, 11:42 PM

from what i have read, its just cold or weak solder points on the amp's pcb. its a pretty simple board, with about 30 or so resistors, a ic or two and a rectifier or two as well. just be careful with pull through when youre reheating the points and you should be fine. use a lower watt iron with a good tip. watch for bridging. wash the pcb with cleaner or alcohol and you should be ok. i say this from building circuits myself so....to me its second nature.
im thinking my only other problem now is something to do with the cable to the actuator or my speed sensor...when i set the cruise...it accelerates upt to 5 mph before setting. so if i want it at 65...i have to actually set it at 60.

pizzachef · #15 02-11-2007, 02:30 PM

Quote:

Originally Posted by ForcedInduction

Send it here: http://www.gdl-online.com/begin1.html

Holy cow, $215 to exchange my broken amp for a good one...that's quite a charge for basically the labor..am I missing something?

Well, I have heard they're ridiculously expensive parts. I'll have to see how mmuch highway driving I'lll really be doing to see if its worth it.
Thanks for the link.
-Geoff