Converting manual steering to power steering s4 n/a
 

Currently working on a plan to get power steering into my car that did not originally come with power steering. The biggest thing I’m trying to decide is if I want to do the electric pump mod or use an oem pump. From what I can figure out the models that didn’t come with ps from factory don’t have the wiring for the pump and ps control module so either I have to source all that or just put it on a switch (correct me if I’m wrong). I’ve seen people talk about having the electric pump mod wired into the wheel speed sensors to slow down at speed or having it on a toggle switch to slow down the pump? Has anyone done a 3 position switch (maybe ps off, full speed, or low speed for highway driving) or anything like it. Or has anyone found a good way to wire up an oem pump?

a friend of mine just did this, and the wiring should be there.

Like j9fd3s says, it should have the wiring already. However, my car (originally '86 base, I think, hard to tell anymore) didn't have the wiring for the rear hatch wiper I added. In the factory service manual Mazda says that the wiring is not present on "low grade" models (gee, thanks). So if you have an early '86 model I would check just to be sure. It should be a two pin connector and a six pin connector, on the harness near the fusebox under the hood.

IMO if you do decide use an electric pump you definitely want some kind of speed sensing function. The switch sounds like a pain for street driving.

I thought the wiring should be there but maybe mines too "low grade". I have never posted pictures on here before so let me know if it doesn't work but here, the red is where the power steering connectors should run correct? Could they be hidden in the harness somewhere like the blue circle? its definitely not the connectors in green under the brake master (yellow) right?
https://cimg7.ibsrv.net/gimg/www.rx7...de50b17472.jpg
Red: where I think the power steering wires should come from.
Blue: where I may open up the harness to make sure the connectors aren't just hidden inside.
https://cimg9.ibsrv.net/gimg/www.rx7...8bbceca21d.jpg
Yellow: brake master
Green: connectors that look right but definitely aren't it?


If I go with the electric pump I agree that the switch would be a pain but all I can find is people talking about how they "have it on a switch temporarily and will add a speed sensing function later". Has anyone done a write up of how to wire the wheel speed sensors to the pump to make it compatible?

Here's a picture of mine. The wiring nearby is not stock, but the power steering wiring comes off the stock fusebox:

https://cimg8.ibsrv.net/gimg/www.rx7...2346e420d4.jpg

It definitely looks like you don't have it. Maybe see if it's tucked under the fusebox, but I don't see as many wires.

For speed sensing you would need a pump that already has that function, or maybe some sort of controller specific for that function. Then wire in the speed sensor from the instrument cluster (green wire w/red stripe). I can't be more specific unfortunately, because I've never done it. I believe the Volvo V50 pumps can do it, so maybe look into that. If they just need a simple VSS signal then you could wire it straight to the existing wire and you'd be good to go. I don't know anything about whether those signals "translate" though, for example if the output from the VSS has a different frequency range for different vehicles. Which is something else you'll have to investigate.

The wiring comes from the fusebox or from the harness under the fusebox?

From the harness under the fusebox.

Okay well in that case I’ll unwrap the harness below just to make sure it’s not in there then if not I’ll have to wire it up another way. Do you think it would be best just to start another thread specifically asking about wiring up the speedo to the pump or do people still see this thread as active? Sorry just not quite sure the best way to ask questions on here yet.

No need to apologize :)

You could make a new post, but I doubt it would get any traction. I did some research a few years ago on this topic and didn't find anyone who had done an electric pump conversion AND wired up the variable assist.

I did a Google search for you and found this:

https://www.corral.net/threads/volvo...2499503/page-4

Pages 3-5 have some interesting content. Looks like there are people offering commercial products that take the VSS signal and convert it into CAN protocol. You might try contacting them to see what they suggest. Otherwise it's 100% custom work and you'll have to sort out the CAN signals for whatever pump you choose.