I've just installed the 3rd cruise amp. on my car and i'm still getting nothing. I know it's possible that all 3 are bad since they all came from high mile cars but i'm starting to think something else is up. Can somebody point me in the direction of a good cruise trouble shooting DIY webpage or give me some hints?

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1985 Mercedes 300DT

www.gdl-online.com has excellent diagnostics for all components.

You might want to check the column switch is working properly - easy to do with a test meter - before jumping into more challenging diagnostics.

If your vehicle has done a lot of miles with cruise switched on then the actuator (the gizmo under the hood that pushes the throttle linkage backwards and forwards) could be shot. One of its common failure modes will fry any cruise amplifier you connect into the system.......

Search this forum for cruise control and expect to read for a few hours.

Cheers

That's a good one.

I've installed three different amps in the '86 and got the same result as you did. But, I've checked the actuator and it's working OK, so the amps must be the culprit.

There are some detailed testing procedures for the actuator at GDL's site:



http://www.gdl-online.com/testproc.html

Are these the same amps that would go in an 83 300SD? If so, I'd take a dead one off of someone. Mine is never coming out and I need a unit so I can get a rebuilt amp and turn one in for the core charge. My bolt is so stripped that I can only bend the tabs back and remove the board itself. I'm sure they wouldn't really like just a raw board...

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B
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1983 300SD

While I'm thinking about it...The fuse for the tach and horn keeps blowing, no matter what size fuse I have in there. If my memory serves me right, this is the fuse for the cruise control as well. So is there a link between the blown fuse and the cruise system that might be able to help me determine the exact problem?

bbeardb, since I have three of these things i'll just give you one for shipping after i figure out the problem...

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1985 Mercedes 300DT

What I ended up doing to be 100% sure was sending in the actuator (under the hood) and the brain (under the dash) and have GSL bench test both components together. Turned out it was my actuator was bad.

At least you'd know for sure!

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~shell
As of 2/2010:
2001 CLK55 0o\=*=/o0
13.6 @ 106mph
10K mi
1984 300SD
260K mi and going and going...
97 S600
46K miles
1991 Sentra SE-R (extremely dorked with)
www.se-r.net

If it is the same fuse for cruise and horn

1. unplug actuator - there is a rectangular plug on the leads that come out of it.

2. replace fuse

If fuse doesn't blow any more, then a distinct possibility your actuator is blown...

That would be very nice of you. Let me know when you get it figured out, and then I'll check to make sure it's the same amp somehow.

Thanks,
B

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B
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1983 300SD

send me a PM in a few days to remind me...

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1985 Mercedes 300DT

I got a cruiser control amp from a 82 I don't need if you need another. I would try resoldering the whole board. Get the solder hot at each lead and let it flow. It got mine working again. Also look at the fuse box. The connectors can get all corroded and the fuses don't make good contact. DISCONNECT THE BATTERY and use some steal wool to clean the leads.

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85 300D Turbo

Use some emory or crocus cloth (or superfine sandpaper) to gently but thouroughly clean and polish the fuseholder contacts and the ends of each fuse. Then try it again

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Bama1


2008 SLK 280, Firemist Red - "Hurricane"
2001 F150 Lariat 4x4, Black on Black - "Badboy"
1982 240D 4 speed survivor -"Pearl" - Donated to Vietnam Veterans
1962 Oldsmobile Dynamic 88 -"Gertrude"

1954 model original owner - ~2.5M
Gray softtop/solid exterior/modified chassis

i've definitely had cleaning the fuse box on the back burner for some time now...i replaced the cruise actuator with one from another car and the fuse still blew...

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1985 Mercedes 300DT