More cruise control trouble shooting

[dshockley]

The 1991 (early) W-250 auto that I bought has cruise control, but it does not work very well. If I am cruising at 65 and set the cruise control then it stabilizes speed around 55. If set at 55-47. It will not allow me to use the accel button once this speed is stabilized. The previous owner told me about this condition and added that it had always been this way. While under warranty, he had it in the shop several time and always the same, it would work slightly better for a few days and then begin to deteriorate. I found two technical service buletins on this system, but they didn't provide information that fixed my problem. Does anyone have any experience with this type of probem or have any ideas on where to begin correcting it. Is there an after market cruise that I could interface with my buttons on the wheel? Thanks for any leads or information. One of the TSB's mentioned an updated control module. The previous owner said that at one time they replaced his, but it did not solve his problem.



Thanks,

Dan

 

[rfitzgarrald]

Originally posted by dshockley

The 1991 (early) W-250 auto that I bought has cruise control, but it does not work very well. If I am cruising at 65 and set the cruise control then it stabilizes speed around 55. If set at 55-47. It will not allow me to use the accel button once this speed is stabilized. The previous owner told me about this condition and added that it had always been this way. While under warranty, he had it in the shop several time and always the same, it would work slightly better for a few days and then begin to deteriorate. I found two technical service buletins on this system, but they didn't provide information that fixed my problem. Does anyone have any experience with this type of probem or have any ideas on where to begin correcting it. Is there an after market cruise that I could interface with my buttons on the wheel? Thanks for any leads or information. One of the TSB's mentioned an updated control module. The previous owner said that at one time they replaced his, but it did not solve his problem.



Thanks,

Dan

Hi, I'm a newbie but I had a problem with my c/c too! I would set it to 65 and it would fall off to 45. I looked in the Chilton manual and it told me how to adjust the cable. I can send you the procedure if you'd like?

 

[dshockley]

Well, I got the chance to mess with it some tonight and what do you know? It made a major improvement. The CC's performance still lacks some in that it drops 4-6 mph before engaging and raising the speed back to the set point, but hey, it works and effectively controls the speed. Another thing that I noticed was though the "accel" key actuates the throttle and accelerates the truck, it does not change the set point and after release the truck slows back down. Was this the standard operation? All the CC's I have used changed the set point.



Thanks for the tip, it really helped me cut down the diagnostic time.



Dan

 

[rfitzgarrald]

Originally posted by dshockley

Well, I got the chance to mess with it some tonight and what do you know? It made a major improvement. The CC's performance still lacks some in that it drops 4-6 mph before engaging and raising the speed back to the set point, but hey, it works and effectively controls the speed. Another thing that I noticed was though the "accel" key actuates the throttle and accelerates the truck, it does not change the set point and after release the truck slows back down. Was this the standard operation? All the CC's I have used changed the set point.



Thanks for the tip, it really helped me cut down the diagnostic time.



Dan

Glad to be of help. Oo. Oo. Oo.



As for your question, my accel switch speeds up the truck & resets the set point, so it sounds like you may have another problem. You could work around it by just using your foot and the set button.