Cruise control not working

[ebouwman]

I was wondering, does anyone know about diagnosing/fixing problems with the mk1's cruise control?

Mine is just plain stupid, half the time when you press the power button it doesn't turn on, so you have to press it a few times for it to go on, then when that goes on you have to fiddle with the set button before it'll set the cruise control, THEN when you finally get the cruise control set it'll kick off, sometimes it'll stay on for half a second, sometimes a few, but it won't stay on.

It's a bit of an issue for me because for the next while i'm going to have to do some highway driving every 10 days, and i have a lead foot, and no radar detector.

Yesterday i did my 300 - 320 km trip and showed up in town with the fuel gauge on empty, whoops...

Although empty doesn't mean empty, it means almost 100 more km's.

If anyone knows much about cruise control it would be awesome! I'm sure it must be something simple, actually, i'm just hoping it is. It would be nice if it's a simple fix, something i could do in the hotel parking lot

[tstoney82]

first, check all the fuses and relays related to the cruise control. if all are good, have a local shop test the switch. it may not be functioning correctly.

i had the same problem with my mk2. i would turn on the cruise, but it wouldnt set most of the time. when it did set, it would only stay on cruise for a short period of time then it would turn off. i checked the relays....good. i checked the fuses....bad. replaced the fuse....worked for a while then it started acting up again. i replaced that fuse several times before i decided to test the switch. (i get lazy about fixing things sometimes) so i tested the switch and found a short in it. this caused my fuses to consistantly pop every time i put a new one in. replaced the switch.....cruise works

[ebouwman]

Well the cruise control works, just not for very long, so it's not the fuses, or at least i just can't see how it would be...

Sometimes it'll work for ten seconds or so, then quit. I'll see if i can take the switch off and test it myself (if i can figure it out) and i'll bust out the haynes manual and start testing relays in the parking lot tomorrow after work!

[tstoney82]

well since you said it does work for a short period of time, then its definitely not going to be a fuse. if it was a fuse, it would work, then not work.....but not work again until it was replaced with another fuse. so it is more than likely a relay or a problem with the switch. keep us informed on what you find.

[ebouwman]

ya, cause at first i thought it could have been a fuse, then thought about it...

I'm going to have to bust out the haynes manual and start studying the cruise control system, but right now i'm a bit wiped, i'll read that tomorrow after work

[muffinman]

Originally Posted by ebouwman

I'm going to have to bust out the haynes manual and start studying the cruise control system, i'll read that tomorrow after work

You will be very disappointed when you get to that section of the book.

IIRC there are two vacuum lines. Make sure you don't have any bad lines , i'll take a look at mine better when i get home.GL

[ebouwman]

Originally Posted by muffinman

You will be very disappointed when you get to that section of the book.

IIRC there are two vacuum lines. Make sure you don't have any bad lines , i'll take a look at mine better when i get home.GL

Ya, WTF? Nothing on the cruise control, gah...

[tstoney82]

alldata or chilton is the way to go. haynes kinda sucks as far as detailed systems sometimes

[tjmr2]

E: I went down this road, spent a long time figuring it out. Long story short, there is a latching relay in the steering column section that failed on my 89. Power would come on, (green LED) and CC would engage, might stay on for 1 mile or 5 then the power light would turn off and CC would of course drop out. Even the BGB barely covers this circuit, and it's really only the schematic that helped me.

The latching relay (Fujitsu) is of course soldered to the board, and of course it's proprietary (only available to Toyota in Japan). And a new CC switch unit will set you back around $170 if I remember correctly.

The good news is you can order a miniature latching relay from Mouser. Remove the original from it's board, solder some extension wires onto the board in the steering column and feed them down under the dash and solder the extension wires onto your new latching relay. Essentially moving the relay to a remote location. I soldered my relay and it's wires on a piece of perforated board and cut it so it would fit in a screw top prescription bottle. It's now wire tied under the dash.

Miniature latching relays (think I used an Omron), are pretty cheap, and the fix wasn't that difficult once I was able to troubleshoot it to the relay (and finding the little bugger). It's the pin spacing that makes it a proprietary relay eliminating your ability to just buy a new relay from another manufacturer and solder it onto the original board. At least that was my finding a couple of summers ago.

Haven't had the CC drop out since then. Hope this helps, good luck.

[muffinman]

sounds like tjmr2 has dealt with this issue before so he may have found your problem but check all the easy stuff first before you start tearing any thing apart. I took a quick look at mine and it has a vacuum line that comes from the intake right by the brake booster vac line , there is also some small lines and what looks like a vsv.

[ebouwman]

Thanks guys, i definitely can't do that relay replacement here, and i'll try to get out tonight and take a look at the vac lines, but i'm kinda beat tonight, our foreman at work has us working 10 hour days everyday, and today decided that he needed to make it an 11 hour day.

[88-4age]

i said **** it and took off my cruise....

[Jackstand Queen]

The best approach I can come up with is to find a junkyard Mr2, and buy in this order the Control Stem (off the steering column), The CC computer, mounted on the left side of the rear trunk firewall. The last and least likely to quit working is the Vacuum pump and diaphram unit mounted in the engine bay. Its also going to cost the most.

Before hitting the junkyard, you might check the ground(s) on the engine bay piece. The whole issue could be just a corroded terminal.

The part that seems to wear out first in CC is the Control stem. FYI

Good Luck.

[ebouwman]

Originally Posted by Jackstand Queen

The best approach I can come up with is to find a junkyard Mr2, and buy in this order the Control Stem (off the steering column), The CC computer, mounted on the left side of the rear trunk firewall. The last and least likely to quit working is the Vacuum pump and diaphram unit mounted in the engine bay. Its also going to cost the most.

Before hitting the junkyard, you might check the ground(s) on the engine bay piece. The whole issue could be just a corroded terminal.

The part that seems to wear out first in CC is the Control stem. FYI

Good Luck.

Thats what i was thinking...

Back in PG there's one in a junkyard, i kinda don't want to talk to the guy cause i hate him, but i might go in there when i get back to town. I'm not totally sure if it has CC but it most likely does as it's got power locks and windows.

I'll take a look at the grounds, i forgot about that one, it could offer a pretty reasonably explanation.

Thanks for the location on the cc computer.

[tjmr2]

The BGB lists a complete step by step procedure for checking the CC computer.

Good luck, intermittent electrical problems can be the hardest to diagnose correctly, and probably the easiest to throw money and parts at.

[efx]

My cruise control stopped working completely and the picture that muffinman posted is what mine looks like too. Okay here you go...to test the cc, I think you turn on the ign key, then press both cc buttons at the same time, it will start blinking. If they are spaced out nicely, I think it goes up to like 15 blinks...going from memory here, then the cc controls are fine. If not, then the you go on to the troubleshooting. Took me a while to figure this out, but it works nicely without taking the whole thing apart. I think I checked my fuses and they looked fine. My cc used to work, and now just doesn't work at all. I thought my actuator might be bad since my vacuum lines seem fine and no burned fuses. I forgot to check my grounds though.

I should note, that my cc lights still come on fine when I press them even though the cc doesn't actuate while driving so I don't think my problem is the relay. But who knows.

Originally Posted by muffinman

sounds like tjmr2 has dealt with this issue before so he may have found your problem but check all the easy stuff first before you start tearing any thing apart. I took a quick look at mine and it has a vacuum line that comes from the intake right by the brake booster vac line , there is also some small lines and what looks like a vsv.

http://carpron.com/multisite/d/357324-2/CAM_0894.jpg

[ebouwman]

Originally Posted by efx

My cruise control stopped working completely and the picture that muffinman posted is what mine looks like too. Okay here you go...to test the cc, I think you turn on the ign key, then press both cc buttons at the same time, it will start blinking. If they are spaced out nicely, I think it goes up to like 15 blinks...going from memory here, then the cc controls are fine. If not, then the you go on to the troubleshooting. Took me a while to figure this out, but it works nicely without taking the whole thing apart. I think I checked my fuses and they looked fine. My cc used to work, and now just doesn't work at all. I thought my actuator might be bad since my vacuum lines seem fine and no burned fuses. I forgot to check my grounds though.

I should note, that my cc lights still come on fine when I press them even though the cc doesn't actuate while driving so I don't think my problem is the relay. But who knows.

Doesn't sound like a fuse then really, don't have a wiring diagram in front of me but if the cc fuse went i don't think that the power would even go on on the stick.

Also if anyone could give me the link for a bgb for an 86 auto that would be AWESOME. I still don't have a copy

EDIT: i just did that check thing and it kept on blinking 5 times then pause then 5 times, again and again. So i'm going to assume that that means there's something wrong, so anyone know what that issue is?

[muffinman]

Originally Posted by ebouwman

Also if anyone could give me the link for a bgb for an 86 auto that would be AWESOME. I still don't have a copy

I have never seen the BGB for an 86. The only one i know of is the 88 and 89. Is there an 86 BGB download?

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[efx]

I think it should be the same. But there's a bunch of codes here...two main Type A and a set for type B. You did the test for Type A which is the first set. Unfortunately theres no five on and five off, but there is a 3 on and 3 off which means the accel/resume switch circuit is normal. Oops, yours I think is the next one...I see five on and then just off, so I assume that may be what you have, but that just means that the vacuum switch circuit is also normal.

For the test B you have to turn the ign on, then the set/coast switch on three times within two seconds and then read the diagnostic on it. If spacings are .25 seconds apart your normal. Normal codes continues 20 seconds and abnormal codes are repeated three times. Looking at this mess I may have to do them all again since some of them are tough to read.

[tjmr2]

The main problem I addressed was Ebouwman's cruise working then dropping out randomly - with the power light on the stem dropping out at the same time. That's the relay problem.