I have done some very basic troubleshooting on the cruise of my 83 300SD. I have resoldered all of the connections on the amp(which i will do again) and tried holding the "up" on the "joystick" to see if it would gain speed. I had read that when the amp goes if you hold accelerate it will still accelerate. The fuse looks good. Where else should i troubleshoot? the servo was supossably replaced about 2 years ago but looks pretty old to me. is there any way to test these individually? thanks for the replies,
R

You want to assure that your vacuum system is holding vac pressure.

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Matt
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1995 E300 Diesel (Die Blau Frau)

I was ordering parts on Fastlane and noticed a fuse for the cruise control amp.
Is this just the fuse that also applies to the ux. fan, windows etc.? or an independant fuse? The price seems to indicate an independent fuse.
Where is it located??
re: '79 300D

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1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

Ryan,

I'm having intermittent problems with my '85 300SD cruise too. It's funny you mention the bit about holding the accelerate and it picks up speed....mine does that; didn't realize it meant anything tho.

On mine, the CC sometimes engages and most of the time it doesn't. When it does, it holds speed perfectly. Seems to me that if it EVER works at all, then the amp and other part must be good...maybe a bad connection in the actual hand lever?

Where did you read about those CC troubleshooting tips?

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Chris
1985 300SD - 'Grace' (198K mi.)
2018 Honda Civic Sport
2018 Honda CRV LX
2010 Honda Fit Sport (RIP)
2013 Honda Accord Sport (Sold)
1996 Lexus LS400 (Retired)
1995 Ford Contour SE (Retired)
1976 Porsche 914 (Sold)
1972 Datsun 240Z (RIP)

If you hold the lever and it accelarates,than you need a new or rebiult amp.

Michael:

But if the CC works sometimes and holds speed when it IS working, does this STILL mean that I need a new amp?

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Chris
1985 300SD - 'Grace' (198K mi.)
2018 Honda Civic Sport
2018 Honda CRV LX
2010 Honda Fit Sport (RIP)
2013 Honda Accord Sport (Sold)
1996 Lexus LS400 (Retired)
1995 Ford Contour SE (Retired)
1976 Porsche 914 (Sold)
1972 Datsun 240Z (RIP)

simply put: yes. You can try to resolder the old amp, there is a write up of it somewhere on the net, type in cruise control repair, in google.com and you should come up with something. Keep in mind if you do this then you lose the ability to sent it off to be rebuilt or lose it's value as a core charge
Ryan

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83 300SD.......sold
96 integra SE....sold
99 a4 quattro....sold
2001 IS300.......sold
2002 330i.........current.
2004 highlander limited....current.

Ok. You happen to know what range of repair/replacement costs I'm looking at to send it off for repair the?

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Chris
1985 300SD - 'Grace' (198K mi.)
2018 Honda Civic Sport
2018 Honda CRV LX
2010 Honda Fit Sport (RIP)
2013 Honda Accord Sport (Sold)
1996 Lexus LS400 (Retired)
1995 Ford Contour SE (Retired)
1976 Porsche 914 (Sold)
1972 Datsun 240Z (RIP)

get in touch with peter@gdl-online.com
I just got mine back. It was rebuilt with a one year warrently. $185 I think it came to.

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Jim

enga...ok thnx. So it's an under $200 repair then.

Just need to find out if it's maybe the actual switch in the steering column or maybe vacuum related first.

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Chris
1985 300SD - 'Grace' (198K mi.)
2018 Honda Civic Sport
2018 Honda CRV LX
2010 Honda Fit Sport (RIP)
2013 Honda Accord Sport (Sold)
1996 Lexus LS400 (Retired)
1995 Ford Contour SE (Retired)
1976 Porsche 914 (Sold)
1972 Datsun 240Z (RIP)

Here is the link - it tells you how to troubleshoot the system to tell which part has problems. The majority of the time it is the amp in my experience.

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

These are good people to deal with.

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Jim

Jim:

Thnx for that great link!

I've already been talking with someone there via email. He's been very responsive extremely helpful.

Based upon my system's symptons, he really feels that it's the amp. He's said I could even send in the amp to be fully tested for a small charge...to prevent me from just buying a new and finding out it was NOT the problem.
I'll prolly go ahead and do this...will save me a lot of time and agravation.

__________________
Chris
1985 300SD - 'Grace' (198K mi.)
2018 Honda Civic Sport
2018 Honda CRV LX
2010 Honda Fit Sport (RIP)
2013 Honda Accord Sport (Sold)
1996 Lexus LS400 (Retired)
1995 Ford Contour SE (Retired)
1976 Porsche 914 (Sold)
1972 Datsun 240Z (RIP)