Has anyone heard of a cruise control issue caused by a faulty gear position switch in a D1 (1997)? I have replaced vacuum hoses, T-connector, vacuum pump, and most recently, the ECU. But what I noticed now is that the light on the cruise control switch is bright red when the automatic transmission in park and neutral, off when in reverse, and very, very dim when in any of the forward gears. The dim light made me think it was the ECU but now I am wondering if something is telling the ECU that I am not in a forward gear so it is not engaging. Any thoughts?

 

It reads the neutral safety switch which is engaged when in park or neutral. It's ECU uses the instrument panel (speedometer) when in forward motion and will only engage once over 28 mph. If it's not engaging then I'd suspect the instrument panel (grey/pink wire) is in need of a look. Also the brake pedal switch might be the other problem child. Both will disable the Cruise (disable relay) if not working correctly.

 

Did you convert over to a D2/P38 ECU? Way more reliable vs the Lucas unit. I recently attacked the CC on my 98 and I had 3 dead parts. Vacuum lines, brake switch, and the ECU. I grabbed a pigtail from the junk yard off a D2, and the CC ECU. I completely cut my OEM harness off, and spliced in the pigtail with the proper wire colors. Cruise Control works fantastic now!

 

I had mine going but it sucked more fuel than my foot.

 

Really? I just drove up to Ely, MN and back and averaged 16-17mpg totally on Cruise. I was pleasantly surprised with that.

 

I forget what life's like in flat land..... Our state highways in three directions are glacial deposits - hills. The cc pegs the pedal. Never noticed it so much as in the land slug.