1st Gen. Ram - All Topics Discussion for all Dodge Rams prior to 1994. This includes engine, drivetrain and non-drivetrain discussions. Anything prior to 1994 should go in here.

Will a bad TPS prevent cruise control operation?

Thread Tools
 
Search this Thread
 
Old May 14, 2016 | 12:13 PM
  #1  
feets's Avatar
Thread Starter
Registered User
 
Joined: Dec 2002
Posts: 330
Likes: 8
From: DFW, TX
Will a bad TPS prevent cruise control operation?

I'm troubleshooting the cruise control on my 92 D250. The FSM makes mention of codes 34, 15, and 11 in the speed control section but not 24 (TPS).

I know the TPS is shot. That's why I use governor pressure to trigger OD.
Reply
Old May 14, 2016 | 01:02 PM
  #2  
j_martin's Avatar
Registered User
 
Joined: Nov 2011
Posts: 4,479
Likes: 211
From: Isanti, MN
Cruise isn't even mentioned in the Powertrain Diagnostics Procedures manual. I don't think TPS would be involved, though, because there is no TPS on a manual transmission.

The most common faults for cruise are:

CPS, which will also drop OD (not in your case of course) and alternator fielding.

The switches in the steering wheel.

The clock spring in the steering column.

Vacuum problems at the control.
Reply
Old May 14, 2016 | 04:13 PM
  #3  
feets's Avatar
Thread Starter
Registered User
 
Joined: Dec 2002
Posts: 330
Likes: 8
From: DFW, TX
I checked the switch and when the resume button is pressed it has continuity across all pins. I'm pretty sure that's an oopsie and a new switch is in order.

I don't think that would prevent the system from operating unless it let the smoke out of something. It's a start.
Reply
Old May 15, 2016 | 01:05 PM
  #4  
j_martin's Avatar
Registered User
 
Joined: Nov 2011
Posts: 4,479
Likes: 211
From: Isanti, MN
Originally Posted by feets
I checked the switch and when the resume button is pressed it has continuity across all pins. I'm pretty sure that's an oopsie and a new switch is in order.

I don't think that would prevent the system from operating unless it let the smoke out of something. It's a start.
If the on/off switch is on, then when you press the resume button there should be continuity across all pins. Without diagrams you are just guessing.

How about continuity through the clock spring? That's best checked out with a voltmeter at the switches.
Reply
Old May 16, 2016 | 11:09 AM
  #5  
cougar's Avatar
Registered User
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2009
Posts: 3,317
Likes: 485
From: alaska
On my 92, when I adjust the TPS it affects the cruise control either by overshooting or undershooting the set speed.
Reply
Old May 16, 2016 | 04:35 PM
  #6  
feets's Avatar
Thread Starter
Registered User
 
Joined: Dec 2002
Posts: 330
Likes: 8
From: DFW, TX
I found a bad resume switch on the steering wheel. New switches are not available in the aftermarket. I didn't bother checking the dealer.
A friend is more familiar with electronics repair than I am so I took the switch to his place. We tore it apart and desoldered the bad microswitch. Mouser has one for 59 cents. It'll be a quick solder job with 4 pins and I'll be able to continue checking the system.

The FSM says that with ON and RESUME both in the on position there should be continuity across 1 and 3, not all four.
Originally, I had continuity across all four but it dropped dead before we took the switch apart.
Reply
Old May 18, 2016 | 09:01 AM
  #7  
mhuppertz's Avatar
Registered User
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2004
Posts: 4,053
Likes: 135
From: Tijeras, New Mexico, 7,000ft up
Glad you found it. My resume switch doesn't work but the cruise still does (when the brake switch isn't acting up). I was going to mention my cruise not working because of a bad brake switch, but you found the issue before I could!


I want to hear more about the Belvedere. Will PM you!




Originally Posted by feets
I found a bad resume switch on the steering wheel. New switches are not available in the aftermarket. I didn't bother checking the dealer.
A friend is more familiar with electronics repair than I am so I took the switch to his place. We tore it apart and desoldered the bad microswitch. Mouser has one for 59 cents. It'll be a quick solder job with 4 pins and I'll be able to continue checking the system.

The FSM says that with ON and RESUME both in the on position there should be continuity across 1 and 3, not all four.
Originally, I had continuity across all four but it dropped dead before we took the switch apart.
Reply
Old May 19, 2016 | 05:50 AM
  #8  
peckens's Avatar
Registered User
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Nov 2010
Posts: 691
Likes: 102
From: Winterset, IA
Originally Posted by feets
I found a bad resume switch on the steering wheel. New switches are not available in the aftermarket. I didn't bother checking the dealer.
A friend is more familiar with electronics repair than I am so I took the switch to his place. We tore it apart and desoldered the bad microswitch. Mouser has one for 59 cents. It'll be a quick solder job with 4 pins and I'll be able to continue checking the system.

The FSM says that with ON and RESUME both in the on position there should be continuity across 1 and 3, not all four.
Originally, I had continuity across all four but it dropped dead before we took the switch apart.
Care to share the part# or link?
Reply
Old May 19, 2016 | 04:54 PM
  #9  
feets's Avatar
Thread Starter
Registered User
 
Joined: Dec 2002
Posts: 330
Likes: 8
From: DFW, TX
Originally Posted by peckens
Care to share the part# or link?


A quick google search brought up this one:

Tact Switches 4.5 x 4.5mm (through hole) - push button height 3.5mm TS-1801, View 4.5mm tact switch, FOSEN Product Details from Dongguan Fosen Electronics Technology Co., Ltd. on Alibaba.com

It's the same dimensions and function.
Reply
Old May 22, 2016 | 09:59 PM
  #10  
feets's Avatar
Thread Starter
Registered User
 
Joined: Dec 2002
Posts: 330
Likes: 8
From: DFW, TX
It works!

The switch was delayed but it came in yesterday and my friend put it together for me. He brought it to me when we met for dinner tonight.
Being the tinkerer that I am, I installed the switches in the parking lot and had cruise control on the way home.

For some reason I am giddy almost to the point of being silly that my cruise control works again. I just knew it was going to have faults elsewhere. It hasn't worked in the better part of 10 years and I rarely used it when it did.

My cruise control works.
Reply
Old May 23, 2016 | 08:43 AM
  #11  
j_martin's Avatar
Registered User
 
Joined: Nov 2011
Posts: 4,479
Likes: 211
From: Isanti, MN
Cruise Control Switches

On - off Omron D2F-d (Micro solder lugs)

Set - Omron D2F (printed circuit)

Resume 4.5mm (3 x 5mm PC holes) snap in tactile switch

Alps SKHRABA010

Mouser should have them all.
Reply
Old May 23, 2016 | 10:14 AM
  #12  
feets's Avatar
Thread Starter
Registered User
 
Joined: Dec 2002
Posts: 330
Likes: 8
From: DFW, TX
Yep. Mine came from Mouser.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
whosdunit
1st Gen. Ram - All Topics
5
May 17, 2014 08:54 AM
Lurch519
24 Valve Engine and Drivetrain
5
Feb 4, 2010 07:09 AM
Landini1
3rd Gen Engine and Drivetrain -> 2003-2007
1
Dec 15, 2009 01:17 PM
truckbouy2
3rd Gen Engine and Drivetrain -> 2003-2007
10
Mar 29, 2008 10:48 AM
dzpoorjr
1st Gen. Ram - All Topics
3
Jan 22, 2005 10:29 PM




All times are GMT -5. The time now is 07:07 PM.