Cruise control issues

[Polloso]

I have a 89 K1500 that I did a lq4/4l80e swap. I used a holley terminator x max and all works very well except the Cruise. Not sure if it worked before the swap. I replaced the stalk with a new delco unit. I've followed all diagnostic flow charts in the manual and still have no Cruise. The drac is build into the IP cluster as I added dip switches to get the proper calibration after gears and tires. The speedo is dead nuts as in comparison to what the holley handheld is seeing as far as speed. I'm at a loss and have a few questions.

1. Will the Cruise work without the stock ecm? I have verified while troubleshooting I am getting a buffer signal to the module from the IP.

2. This one is silly but must be asked, what is the minimum speed to assert Cruise?

3. I already have went to the junkyard to get a new module. I got one off a gmt800, they look almost identical. Should that work or do I need one off a gmt400?

 

[someotherguy]

1. don't know the answer to that one but some careful examination of the wiring diagrams specific to your year model might help. There's links to free service manual downloads in the forum.

2. IIRC it's 30 or 35 mph, probably 30, anything lower and it shouldn't allow activation. A glimpse through the owner's manual would answer that if absolutely necessary; I probably have a '94 manual handy somewhere.

3. Probably, providing you replace the cable with your existing one. The cruise modules don't often go bad but they are getting to the age where some are seeing failures caused by bad solder joints, similar to what happens to everyone's wiper circuit board.

Richard

 

[Polloso]

Thanks for the reply, I was able to get a 1989 service manual before I began with the restoration of the truck as it was crucial with other wiring. My guess is the ecm only gets a buffer signal from the IP as well and isn't necessary for Cruise operation. The brake switch tests good as does all the wires at the module (12v switched, gnd, on/off, etc). I did keep the same cable that came witht he truck. I guess I'll return to the bone yard to swap for a unit from a 88-98. I opened up the old module and ohm checked the pins to their respective points on the board, all .5 ohms.

 

[df2x4]

2. IIRC it's 30 or 35 mph, probably 30, anything lower and it shouldn't allow activation.

I'll second this as being in the ballpark for sure, at least for the '96+ trucks. I tested how low I could go with the cruise in my '97s a couple times and IIRC it was right around 30MPH.

 

[packer0440]

I was having this issue recently, new module fixed it. MAKE SURE YOU GET AN 88-93 MODULE. 94-up will not work on the earlier trucks; I tried multiple newer ones and had no success. Got an earlier unit and works great

 

[someotherguy]

I was having this issue recently, new module fixed it. MAKE SURE YOU GET AN 88-93 MODULE. 94-up will not work on the earlier trucks; I tried multiple newer ones and had no success. Got an earlier unit and works great

I noticed that Blue Streak (BSE) rebuilds the cruise modules, though at Rock they're out of stock. They showed two different part #'s when I looked them up; didn't dive deeper than that as it expected me to have a GM # to cross-ref.

Richard

 

[packer0440]

I noticed that Blue Streak (BSE) rebuilds the cruise modules, though at Rock they're out of stock. They showed two different part #'s when I looked them up; didn't dive deeper than that as it expected me to have a GM # to cross-ref.

Richard

If you look at the pigtail there are 3 more pins on the newer ones and the circuit board is way different. I assume this has to do with the newer style brake switch and pcm possibly. There are a couple different part numbers on the older style but it seems like they interchange between 88-93.

 

[someotherguy]

If you look at the pigtail there are 3 more pins on the newer ones and the circuit board is way different. I assume this has to do with the newer style brake switch and pcm possibly. There are a couple different part numbers on the older style but it seems like they interchange between 88-93.

It's good stuff to know. In the past, I'd never had to look into it as the cruise modules are pretty robust and we're only starting to see failures of them crop up in the last few years. Not saying none at all failed prior, but not in any significant numbers to where it would be much of a subject.

Richard

 

[Polloso]

Ok cool I'll take it back and get a 88-93 unit. I'll post up once I do and let yall know the result. Thanks for the replies fellas!

 

[sntrym]

Cruise operation is minimum 25 mph on almost every car. Some are 30, but the GMTX00 trucks are 25.