Help locating the tach wire going into digital dash

I am moving along with my after market Rostra cruise control install. I have the mounting all flushed out and have located and tapped into the vehicle speed sensor wire (violet/white) that goes into my the back of my instrument cluster but am trying to find the tach wire. Does anyone know which wire it is or how to test for it?

Hello

I can’t help directly but would recommend the wiring diagrams found on the Hiace Southeast website. See here: https://www.hiacesoutheast.com/hiace-manuals

I can’t be sure that the tach wire will be included but this is the most comprehensive and easy to navigate wiring diagram set I’ve ever seen for the Hiace; many of the others out there are disjointed and not easy to follow.

An aftermarket cruise control is something I’m looking to fit to my van as I have cc on my car (which is also a manual) and I find using cc a much more relaxing way to drive when conditions allow. It’s especially useful in areas with average speed cameras, too.

Anyway which cc have you gone for, please? Is it a ‘universal’ kit or a model-specific variety as I presume your van has an ECU?

I looked into this last year, but didn’t draw any conclusion on what to get, neither specific kit nor make even. Grateful if you can add anything here or have you created an installation post? Be good to see how you’ve done the installation, too? Can you add any pictures? Is it on a stalk or buttons? Does your van have a tach? Mine does not, but it’s another thing I’d like to add and don’t know whether this could be included within the instrument cluster (I did this on a diesel turbo Peugeot as the wiring was all present despite a manual injection pump etc), or whether an additional gauge would have to located elsewhere. I don’t know whether I have the wiring, too? Mine is a 3L engine but I’ll start to look into the wiring needs and related installation options, but welcome your work to hopefully avoid dead ends.

Thanks

Hi again.

I’ve been doing a little digging on the Rosta site and watched their YT installation video and had a browse through their manuals. Seems a clever enough system that doesn’t seem too hard to install, hopefully, though the Hiace vehicle layout might complicate things a bit? How have you found it?

I still cannot answer your question but I have a few more of my own, sorry!

1 - Where are you / have you located the cruise module? I don’t think inside the engine bay is ideal, but I don’t think it’ll fit anywhere else.

2 – To generate the vehicle speed signal did you know you’d have this electronically or did you contemplate doing this via the speedometer cable with the adaptor such as this: https://www.rostra.com/manuals/250-4160_59A-02361G.pdf?

Finally, another resource that might be useful for the meters is here: https://toyota.epc-data.com/regius_ace/lh119v/114894/electric/8301/. This is for my van but it seems comprehensive. If you’ve not used this I recommend tailoring it to your specific vehicle. It’s very handy.

HTH

I have been using the wiring diagrams you mentioned for all my other work.  Just can't figure the tach wire.  It's not required but more a safety option for the cruise control if knocking the van out of gear while in cruise mode.  You have lots of questions.  I'll bullet the answer below.

-Kit I used:  Rostra 250-1223 and Rostra 250-3742

-Is it getting VSS signal from ECU?:  Yes.  It's a violet/white wire.  You can tap at the ECU or through a multimeter on one end and find the wire closer to where mounting the unit.

-Have I created an installation post?:  No.  I wish I had the time to step it all out but I just used this post as a guide (https://hiace-super-custom.forumotion.com/t2643-cruise-control-tach-wire).  Their photos are no longer live so I can post some newer pictures.  I'll add them to the bottom of that post to keep things relevant.  

-Tach?:  My van has a tach.

-Where is the cruise control model located?:  I put it just behind my cup holder.  I ran the control cable through a small hole in the firewall.

-Was the speed signal obtained electronically?:  See above for ECU VSS signal.

Hope that all helps.

Many thanks.

I'm going to have a look and see if my van has any tach wiring (as it doesn't have a tach in the clocks). The earlier link to the gauges suggests there might be something built into the injector pump but the thing that part "83180-60080" goes into (see: https://toyota.epc-data.com/regius_ace/lh119v/114894/electric/8301/83180/) is not obvious. It might be the pump.

You wrote about the cruise control taking the VSS from the vehicle's ECU, which I get. My van has the 3L engine and I don't think it has much of an ECU. There are some boxes with electronics inside and the biggest is this one:




and I think this is what passes for an ECU on my van. Part 077300- seems to repate to ECUs on other Toyotas of a similar age.

I'll take a look at the wiring loom and diagrams for the vehicle speed sensor wire (violet/white) as you say there, plus on the gauges (even if there's no tacho there might be the wiring for it, which would be handy).

Failing this, I'll be adding Rosta signal kit that's an adaptor for the speedometer cable. Rosta part 250-4160 or -04153 as necessary.

Cheers and I look forward tro seeing any pictures that you might be able to add to the other post.