Will a bad TPS prevent cruise control operation?
05-14-2016, 12:13 PM
#1
Registered User
Thread Starter
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.
I know the TPS is shot. That's why I use governor pressure to trigger OD.
05-14-2016, 01:02 PM
#2
Registered User
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.
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.
05-14-2016, 04:13 PM
#3
Registered User
Thread Starter
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.
I don't think that would prevent the system from operating unless it let the smoke out of something. It's a start.
05-15-2016, 01:05 PM
#4
Registered User
How about continuity through the clock spring? That's best checked out with a voltmeter at the switches.
05-16-2016, 11:09 AM
#5
Registered User
On my 92, when I adjust the TPS it affects the cruise control either by overshooting or undershooting the set speed.
05-16-2016, 04:35 PM
#6
Registered User
Thread Starter
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.
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.
05-18-2016, 09:01 AM
#7
Registered User
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!
I want to hear more about the Belvedere. Will PM you!
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.
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.
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05-19-2016, 05:50 AM
#8
Registered User
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.
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.
05-19-2016, 04:54 PM
#9
Registered User
Thread Starter
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.
05-22-2016, 09:59 PM
#10
Registered User
Thread Starter
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.
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.
05-23-2016, 08:43 AM
#11
Registered User
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.
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.
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