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Help with starter circuit wiring needed

Its an 1988 Camry 4 cyl station wagon. Sometimes the starter works fine, sometimes there is just a click. Been like this for the 2 years I have had the car. There is an intmt. voltage drop of about 2 volts in the wiring for the starter control terminal. Whenever it fails, I just jump from the battery direct to the starter control terminal, and it never fails to start then. Thought it might be a bad neutral start safety switch, but I removed it without getting off the PARK position and ohmed it out----- it is not resistive at all. So I thought it must be a bad ignition switch. When it has failed I am reading only 10 volts at the black wire with white stripe, which I know feeds power to the starter control terminal. No wonder....a 2 volt drop to 10 volts would indeed give you a 'click'/no-start. But I found that the terminal that is on the *input* side (toward the battery) of the starter engage contact (of ignition switch) is also dropping to 10 volts! This is a solid brown wire. So I have a problem ahead of the iginition switch even. Maybe it is a bad relay or connection to a relay in that black relay box on the drivers side fender well? I can't tell where this wire goes to, as all the ign switch wires just go into a bundle in the steering column. THe simple fix is just to run a new wire from some point that is hot whenever the key is turned to the ON position....but I'd rather track it down and fix properly than do a band-aid fix. I can't find my Camry manual at the moment, and even when I had it, the wiring diagrams didn't correspond too well to what I actually have. If any one can give me a heads' up where that brown wire (the one feeding power through the ign switch to energize the starter) is connected to, I'd appreciate it. That is where my bad connection is.

Thanks, geronimo

Reply to
geronimo
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If you want to start a thread at toyotanation.com and pm me, i can sling some diagrams your way.

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Reply to
qslim

Another source of diagram is Figure 15 on the Autozone's free guide:

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Starter relay (the diagram doesn't show one for the 88 automatic) is downstream of the ignition switch. Maybe the voltage drop caused Toyota to add a relay to later Camrys, as shown in the diagrams.

It's probably in the wiring and/or dirty connections if you are seeing a voltage drop at the input of the ignition switch. Because that switch is HOT at all times. Which means it goes directly to the battery.

If you have 7.5A IGN fuse, you might want to turn the key to ON (not START), and see what kind of voltage you measure across the 7.5A IGN fuse. It should also be 10V when you're having problems. If you have the ALT fuse link or AM1/2 fuse links like in later models in the fuse box these should yield battery voltage even when you have problems. After this you know it's probably the wiring between the fuse link block and the ignition switch.

Reply to
johngdole

guide:

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Reply to
johngdole

Also, when you measure 10V on the input of the ignition switch, the switch is at OFF, right?

Reply to
johngdole

No, it is at full batt voltage until I go from ON to START.... then because there is resistance going back to the battery, it drops to 10 volts. That is why I know it is not the IGN. switch contact that is bad, it is upstream from the ign. switch. As I recall, there are three fuses or fusible links that are mounted right on the pos. terminal of the battery. Obviously starter power has to be going through one of these. Maybe that is where bad connection is? Geronimo

Reply to
geronimo

Well, the only schematics I could find are the ones on AutoZone for the 1988 Camry. And that one doesn't show there is a Starter Relay!! I am surprised because of the amount of current going to the starter (250-400 amps for 97+ models).

So if you have full battery voltage at the IGN SWITCH until you turn it to START, then it's probably the voltage drop by the starter.

You can do a test by jumpering not from the battery but from the INPUT of the IGN SWITCH to the starter, PROVIDED THAT your car connects directly from the IGN SWITCH to the starter without going through a relay (otherwise it's a over-current for the wires).

If the test succeeded in starting, then you know the current drop across the IGN SWITCH is too much. But I have to be absolutely certain that the model year doesn't use a relay before putting all that current through the brown wire you mentioned.

Can you verify the existence of a starter relay?

Reply to
johngdole

According to Figure 15 of 87-91 Autozone diagram: the (B/W) wire from the IGN SWITCH goes into the Neutral Safety Switch and comes out a (B) wire.

*IF* there is no starter relay, and the starter works jumpering from IGN SWITCH to starter; then the next step would be jumpering from (B) of Neutral Safety Switch to starter.

You know, I didn't realize the 88 was designed to carry starting current on these wires!! So better make sure before the tests.

Reply to
johngdole

If everything else checks out, maybe it's like Honda-man's 99 Camry starting problem? Hard to start the first time, but when it gets going, it gets going.

But I wouldn't try to fix a problem by just replacing parts.

Reply to
johngdole

Again, I have already eliminated the ign switch as the culprit, there is NO appreciable voltage being dropped across the ign switch. The drop is occuring somewhere downstream from battery and upstream from the ign switch. It is BRN B-wire on input, and Black/white going out to safety switch as you said....from there to control wire. During cranking there is 0 volts across the ign contacts. The voltage is being pulled down by resistance ahead of the ign switch towards the battery. I have already jumpered around the safety switch, still had same problem. I initially thought that might be where the voltage drop was. I am thinking that there must be an internal relay in this starter, as the wire going to control relay is only abt 20 gauge. It would never handle 200-400 amps! This is is a new starter from Autozone.....a new starter wasn't the fix either! There are three fuses mounted right on the pos terminal of batttery, but none of the four wires are solid BRN. There is something wrong with the middle 60 amp fuse, as it will not pull out, so I am going to investigate this today. But since the starter control wire pwr. doesn't go to the battery directly, problem is not at those fuses.

Geronimo

On Fri, 07 Sep 2007 20:00:24 -0700, snipped-for-privacy@hotmail.com wrote:

Reply to
geronimo

Yeah, 2v drop from battery to the (B) wire on the IGN SW is way too much. There should be Again, I have already eliminated the ign switch as the culprit, there

Reply to
johngdole

is ? Has anyone thought to check for poor ground wire connections ? almost sounds to me like a corroded connection ?

Reply to
mred

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