92 4Runner Cruise Control

[FourRunnnnner]

During the past several years I have spent a good amount of time and a relatively large number of $$ putting my 4Runner in good, sound shape. But one problem continues to remain unresolved: the cruise control.

(For the record, I am completely lost when it comes to mechanics. All of the work I'd had done has been done by certified mechanics. Most of it has been done by a very trusted mechanic at a Toyota dealership. By now, he knows my 4Runner inside and out -- and a lot better than I do!)

Here is what *has* been done (forgive me if I use a wrong part's names below. Seems some parts go by different names).

Replaced with used parts:
- the under-the-hood cruise control unit/actuator/module.
- cruise control switches (in steering wheel).
Didn't fix the problem.

Fast-forward one year.... Toyota dealership mechanic (who I trust very much) suggested that "with 99% probability" the "cruise control relay assembly" was bad. Part ordered, installed, and did not fix the problem (although mechanic did say that part *was* bad). So much for 99% probabilities.

Diagnostics now indicate the bad part is/probably is the "cruise control computer assembly" AKA electronic control unit (ECU). Mechanic suggested I find a used cruise control ECU which he will install at no charge. (He didn't charge me to replace the $132 relay assembly either.)

I questions are: if I replace the computer assembly/ECU and the cruise control still doesn't work what *else* could be wrong? Is the ECU indeed the final 1% of what could possibly need replacing? I'm beginning to feel as though I am chasing a costly, elusive dream.

Thanks in advance.

[ZAchole]

Wiring? Has that all been checked? All your parts may be good, but if they can't talk to each other, they won't work. I think that's vacuum operated, are the lines good? Is it pulling vacuum? Maybe the port is plugged.
A bad ECU is uncommon in Toyota land. But, it could be your problem just the same.